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Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE (Open Access)

Catch me if you can: personality drives technique-specific biases during live-capture trapping

Kyla Chloe Johnstone https://orcid.org/0000-0001-8629-6276 A B C , Clare McArthur A and Peter Bruce Banks A
+ Author Affiliations
- Author Affiliations

A School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia.

B Manaaki Whenua – Landcare Research, PO Box 69040, Lincoln 7640, New Zealand.

C Corresponding author. Email: johnstonek@landcareresearch.co.nz

Wildlife Research 48(8) 713-721 https://doi.org/10.1071/WR20121
Submitted: 27 July 2020  Accepted: 15 May 2021   Published: 21 June 2021

Journal Compilation © CSIRO 2021 Open Access CC BY-NC-ND

Abstract

Context: Wildlife surveys often rely on a single live-capture technique to sample animal populations. Yet, animal personality (e.g. bold vs shy) can drive heterogeneity in capture probability, leading to biased sampling during live-capture trapping surveys.

Aims: We tested whether a personality-related capture bias is similar between two live-capture techniques, or whether techniques with different capture mechanisms are biased towards certain spectrums of personality.

Methods: We compared two live-capture techniques commonly used for surveying lizards, namely, noosing and pitfall traps. Techniques were deployed several days apart to survey populations of a desert-dwelling agamid, the military dragon, and we used outdoor open-field arenas to test for personality traits relating to boldness, activity and exploration.

Key results: We found that noosing and pitfall traps sampled distinctly different spectrums of personality, with no individuals being captured by both techniques. Unexpectedly, noosing, which involved people approaching dragons to capture them, was biased towards shyer individuals that stayed close to shelter. In contrast, pitfall traps, which were generally set in open areas, were biased towards capturing individuals that moved further from shelter.

Conclusions: We demonstrated that different live-capture techniques can be biased towards different spectrums of personality. We attribute the relationship between personality and technique to an interaction between the capture mechanisms of each technique and individual perceptions of risk and microhabitat use.

Implications: To overcome biased and selective sampling and target individuals along a broad spectrum of personality, surveys should use complementary techniques that vary in their capture mechanisms.

Keywords: applied ecology, behaviour, ethology, mark–recapture, wildlife management.


References

Beacham, T. D., and Krebs, C. J. (1980). Pitfall versus live-trap enumeration of fluctuating populations of Microtus townsendii. Journal of Mammalogy 61, 486–499.
Pitfall versus live-trap enumeration of fluctuating populations of Microtus townsendii.Crossref | GoogleScholarGoogle Scholar |

Biro, P. A., and Dingemanse, N. J. (2009). Sampling bias resulting from animal personality. Trends in Ecology & Evolution 24, 66–67.
Sampling bias resulting from animal personality.Crossref | GoogleScholarGoogle Scholar |

Biro, P. A., and Post, J. R. (2008). Rapid depletion of genotypes with fast growth and bold personality traits from harvested fish populations. Proceedings of the National Academy of Sciences of the United States of America 105, 2919–2922.
Rapid depletion of genotypes with fast growth and bold personality traits from harvested fish populations.Crossref | GoogleScholarGoogle Scholar | 18299567PubMed |

Biro, P. A., and Stamps, J. A. (2008). Are animal personality traits linked to life-history productivity? Trends in Ecology & Evolution 23, 361–368.
Are animal personality traits linked to life-history productivity?Crossref | GoogleScholarGoogle Scholar |

Bisi, F., Newey, S., Nodari, M., Wauters, L. A., Harrison, A., Thirgood, S., and Martinoli, A. (2011). The strong and the hungry: bias in capture methods for mountain hares Lepus timidus. Wildlife Biology 17, 311–316.
The strong and the hungry: bias in capture methods for mountain hares Lepus timidus.Crossref | GoogleScholarGoogle Scholar |

Boon, A. K., Réale, D., and Boutin, S. J. O. (2008). Personality, habitat use, and their consequences for survival in North American red squirrels Tamiasciurus hudsonicus. Oikos 117, 1321–1328.
Personality, habitat use, and their consequences for survival in North American red squirrels Tamiasciurus hudsonicus.Crossref | GoogleScholarGoogle Scholar |

Broome, L. S. (2001). Density, home range, seasonal movements and habitat use of the mountain pygmy‐possum Burramys parvus (Marsupialia: Burramyidae) at Mount Blue Cow, Kosciuszko National Park. Austral Ecology 26, 275–292.
Density, home range, seasonal movements and habitat use of the mountain pygmy‐possum Burramys parvus (Marsupialia: Burramyidae) at Mount Blue Cow, Kosciuszko National Park.Crossref | GoogleScholarGoogle Scholar |

Burnham, K., and Anderson, D. (2002). ‘Model selection and multimodel inference: a practical information-theoretic approach.’ 2nd edn. (Springer-Verlag: New York, NY, USA.)

Burns, J. G. (2008). The validity of three tests of temperament in guppies (Poecilia reticulata). Journal of Comparative Psychology 122, 344.
The validity of three tests of temperament in guppies (Poecilia reticulata).Crossref | GoogleScholarGoogle Scholar | 19014258PubMed |

Bury, R. B., and Corn, P. S. (1987). Evaluation of pitfall trapping in northwestern forests: trap arrays with drift fences. The Journal of Wildlife Management 51, 112–119.
Evaluation of pitfall trapping in northwestern forests: trap arrays with drift fences.Crossref | GoogleScholarGoogle Scholar |

Carlson, B. E., and Langkilde, T. (2013). Personality traits are expressed in bullfrog tadpoles during open-field trials. Journal of Herpetology 47, 378–383.
Personality traits are expressed in bullfrog tadpoles during open-field trials.Crossref | GoogleScholarGoogle Scholar |

Carter, A. J., Heinsohn, R., Goldizen, A. W., and Biro, P. A. (2012). Boldness, trappability and sampling bias in wild lizards. Animal Behaviour 83, 1051–1058.
Boldness, trappability and sampling bias in wild lizards.Crossref | GoogleScholarGoogle Scholar |

Carter, A. J., Feeney, W. E., Marshall, H. H., Cowlishaw, G., and Heinsohn, R. (2013). Animal personality: what are behavioural ecologists measuring? Biological Reviews of the Cambridge Philosophical Society 88, 465–475.
Animal personality: what are behavioural ecologists measuring?Crossref | GoogleScholarGoogle Scholar | 23253069PubMed |

Choleris, E., Thomas, A., Kavaliers, M., and Prato, F. (2001). A detailed ethological analysis of the mouse open field test: effects of diazepam, chlordiazepoxide and an extremely low frequency pulsed magnetic field. Neuroscience and Biobehavioral Reviews 25, 235–260.
A detailed ethological analysis of the mouse open field test: effects of diazepam, chlordiazepoxide and an extremely low frequency pulsed magnetic field.Crossref | GoogleScholarGoogle Scholar | 11378179PubMed |

Cooper Jr, W. (2003). Risk factors affecting escape behavior by the desert iguana, Dipsosaurus dorsalis: speed and directness of predator approach, degree of cover, direction of turning by a predator, and temperature. Canadian Journal of Zoology 81, 979–984.
Risk factors affecting escape behavior by the desert iguana, Dipsosaurus dorsalis: speed and directness of predator approach, degree of cover, direction of turning by a predator, and temperature.Crossref | GoogleScholarGoogle Scholar |

Cooper Jr, W. E. (2009). Optimal escape theory predicts escape behaviors beyond flight initiation distance: risk assessment and escape by striped plateau lizards Sceloporus virgatus. Current Zoology 55, 123–131.
Optimal escape theory predicts escape behaviors beyond flight initiation distance: risk assessment and escape by striped plateau lizards Sceloporus virgatus.Crossref | GoogleScholarGoogle Scholar |

Cooper Jr, W. E., and Whiting, M. J. (2007). Universal optimization of flight initiation distance and habitat‐driven variation in escape tactics in a Namibian lizard assemblage. Ethology 113, 661–672.
Universal optimization of flight initiation distance and habitat‐driven variation in escape tactics in a Namibian lizard assemblage.Crossref | GoogleScholarGoogle Scholar |

Cox, M. P., Dickman, C. R., and Cox, W. G. (2000). Use of habitat by the black rat (Rattus rattus) at North Head, New South Wales: an observational and experimental study. Austral Ecology 25, 375–385.
Use of habitat by the black rat (Rattus rattus) at North Head, New South Wales: an observational and experimental study.Crossref | GoogleScholarGoogle Scholar |

Craig, M. D., Grigg, A. H., Garkaklis, M. J., Hobbs, R. J., Grant, C. D., Fleming, P. A., and Hardy, G. E. S. J. (2009). Does habitat structure influence capture probabilities? A study of reptiles in a eucalypt forest. Wildlife Research 36, 509–515.
Does habitat structure influence capture probabilities? A study of reptiles in a eucalypt forest.Crossref | GoogleScholarGoogle Scholar |

Daly, B. G., Dickman, C. R., and Crowther, M. S. (2008). Causes of habitat divergence in two species of agamid lizards in arid central Australia. Ecology 89, 65–76.
Causes of habitat divergence in two species of agamid lizards in arid central Australia.Crossref | GoogleScholarGoogle Scholar | 18376548PubMed |

Davis, S. A., Akison, L. K., Farroway, L. N., Singleton, G. R., and Leslie, K. E. (2003). Abundance estimators and truth: accounting for individual heterogeneity in wild house mice. The Journal of Wildlife Management 67, 634–645.
Abundance estimators and truth: accounting for individual heterogeneity in wild house mice.Crossref | GoogleScholarGoogle Scholar |

Dickman, C. R., Letnic, M., and Mahon, P. S. (1999). Population dynamics of two species of dragon lizards in arid Australia: the effects of rainfall. Oecologia 119, 357–366.
Population dynamics of two species of dragon lizards in arid Australia: the effects of rainfall.Crossref | GoogleScholarGoogle Scholar | 28307758PubMed |

Dingemanse, N. J., and Dochtermann, N. A. (2013). Quantifying individual variation in behaviour: mixed-effect modelling approaches. Journal of Animal Ecology 82, 39–54.
Quantifying individual variation in behaviour: mixed-effect modelling approaches.Crossref | GoogleScholarGoogle Scholar |

Downey, F. J., and Dickman, C. R. (1993). Macro-and microhabitat relationships among lizards of sandridge desert in central Australia. In ‘Herpetology in Australia: a Diverse Discipline’. (Eds D. Lunney, and D. Ayers.) pp. 133–138.

Drew, G. (2016). Divergent habitat selection in two small marsupials in the Simpson Desert, Australia. B.Sc.(Hons) Thesis, The University of Sydney, NSW, Australia.

Efford, M. (2004). Density estimation in live‐trapping studies. Oikos 106, 598–610.
Density estimation in live‐trapping studies.Crossref | GoogleScholarGoogle Scholar |

Enge, K. M. (2001). The pitfalls of pitfall traps. Journal of Herpetology 35, 467–478.
The pitfalls of pitfall traps.Crossref | GoogleScholarGoogle Scholar |

Friend, G., Smith, G. T., Mitchell, D., and Dickman, C. (1989). Influence of pitfall and drift fence design on capture rates of small vertebrates in semi-arid habitats of Western-Australia. Australian Wildlife Research 16, 1–10.
Influence of pitfall and drift fence design on capture rates of small vertebrates in semi-arid habitats of Western-Australia.Crossref | GoogleScholarGoogle Scholar |

Garamszegi, L. Z., Eens, M., and Török, J. (2009). Behavioural syndromes and trappability in free-living collared flycatchers, Ficedula albicollis. Animal Behaviour 77, 803–812.
Behavioural syndromes and trappability in free-living collared flycatchers, Ficedula albicollis.Crossref | GoogleScholarGoogle Scholar |

García-Muñoz, E., and Sillero, N. (2010). Two new types of noose for capturing herps. Acta Herpetologica 5, 259–264.

Garden, J. G., McAlpine, C. A., Possingham, H. P., and Jones, D. N. (2007). Using multiple survey methods to detect terrestrial reptiles and mammals: what are the most successful and cost-efficient combinations? Wildlife Research 34, 218–227.
Using multiple survey methods to detect terrestrial reptiles and mammals: what are the most successful and cost-efficient combinations?Crossref | GoogleScholarGoogle Scholar |

Garvey, P. M., Banks, P. B., Suraci, J. P., Bodey, T. W., Glen, A. S., Jones, C. J., McArthur, C., Norbury, G. L., Price, C. J., Russell, J. C., and Sih, A. (2021). Leveraging motivations, personality, and sensory cues for vertebrate pest management. Trends in Ecology & Evolution 35, 990–1000.

Glen, A. S., Sutherland, D. R., and Cruz, J. (2010). An improved method of microhabitat assessment relevant to predation risk. Ecological Research 25, 311–314.
An improved method of microhabitat assessment relevant to predation risk.Crossref | GoogleScholarGoogle Scholar |

Greenville, A. C., and Dickman, C. R. (2005). The ecology of Lerista labialis (Scincidae) in the Simpson Desert: reproduction and diet. Journal of Arid Environments 60, 611–625.
The ecology of Lerista labialis (Scincidae) in the Simpson Desert: reproduction and diet.Crossref | GoogleScholarGoogle Scholar |

Greenville, A. C., Wardle, G. M., Nguyen, V., and Dickman, C. R. (2016). Spatial and temporal synchrony in reptile population dynamics in variable environments. Oecologia 182, 475–485.
Spatial and temporal synchrony in reptile population dynamics in variable environments.Crossref | GoogleScholarGoogle Scholar | 27337964PubMed |

Harrison, R. L., Barr, D. J., and Dragoo, J. W. (2002). A Comparison of Population Survey Techniques for Swift Foxes (Vulpes velox) in New Mexico. American Midland Naturalist 148, 320–337.
A Comparison of Population Survey Techniques for Swift Foxes (Vulpes velox) in New Mexico.Crossref | GoogleScholarGoogle Scholar |

Herremans, M. (1989). Habitat and sampling related bias in sex-ratio of trapped blackcaps Sylvia atricapilla. Ringing & Migration 10, 31–34.
Habitat and sampling related bias in sex-ratio of trapped blackcaps Sylvia atricapilla.Crossref | GoogleScholarGoogle Scholar |

Kay, B., Gifford, E., Perry, R., and van de Ven, R. (2000). Trapping efficiency for foxes (Vulpes vulpes) in central New SouthWales: age and sex biases and the effects of reduced fox abundance. Wildlife Research 27, 547–552.
Trapping efficiency for foxes (Vulpes vulpes) in central New SouthWales: age and sex biases and the effects of reduced fox abundance.Crossref | GoogleScholarGoogle Scholar |

Krebs, C. J. (1966). Demographic changes in fluctuating populations of Microtus californicus. Ecological Monographs 36, 239–273.
Demographic changes in fluctuating populations of Microtus californicus.Crossref | GoogleScholarGoogle Scholar |

Laves, K. S., and Loeb, S. C. (2006). Differential estimates of southern flying squirrel (Glaucomys volans) population structure based on capture method. American Midland Naturalist 155, 237–243.
Differential estimates of southern flying squirrel (Glaucomys volans) population structure based on capture method.Crossref | GoogleScholarGoogle Scholar |

Liang, J., Tang, S., Nieto, J. J., and Cheke, R. A. (2013). Analytical methods for detecting pesticide switches with evolution of pesticide resistance. Mathematical Biosciences 245, 249–257.
Analytical methods for detecting pesticide switches with evolution of pesticide resistance.Crossref | GoogleScholarGoogle Scholar | 23891583PubMed |

Losos, J. B. (1987). Postures of the military dragon (Ctenophorus isolepis) in relation to substrate temperature. Amphibia-Reptilia 8, 419–423.
Postures of the military dragon (Ctenophorus isolepis) in relation to substrate temperature.Crossref | GoogleScholarGoogle Scholar |

Masters, P. (1996). The effects of fire-driven succession on reptiles in spinifex grasslnads at Uluru National Park, Northern Territory. Wildlife Research 23, 39–47.
The effects of fire-driven succession on reptiles in spinifex grasslnads at Uluru National Park, Northern Territory.Crossref | GoogleScholarGoogle Scholar |

Melville, J., and Schulte, J. A. (2001). Correlates of active body temperatures and microhabitat occupation in nine species of central Australian agamid lizards. Austral Ecology 26, 660–669.
Correlates of active body temperatures and microhabitat occupation in nine species of central Australian agamid lizards.Crossref | GoogleScholarGoogle Scholar |

Merrick, M. J., and Koprowski, J. L. (2017). Should we consider individual behavior differences in applied wildlife conservation studies? Biological Conservation 209, 34–44.
Should we consider individual behavior differences in applied wildlife conservation studies?Crossref | GoogleScholarGoogle Scholar |

Michael, D. R., Cunningham, R. B., Donnelly, C. F., and Lindenmayer, D. B. (2012). Comparative use of active searches and artificial refuges to survey reptiles in temperate eucalypt woodlands. Wildlife Research 39, 149–162.
Comparative use of active searches and artificial refuges to survey reptiles in temperate eucalypt woodlands.Crossref | GoogleScholarGoogle Scholar |

Michelangeli, M., Wong, B. B. M., and Chapple, D. G. (2016). It’s a trap: sampling bias due to animal personality is not always inevitable. Behavioral Ecology 27, 62–67.
It’s a trap: sampling bias due to animal personality is not always inevitable.Crossref | GoogleScholarGoogle Scholar |

Montiglio, P. O., Ferrari, C., and Reale, D. (2013). Social niche specialization under constraints: personality, social interactions and environmental heterogeneity. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 368, 20120343.
Social niche specialization under constraints: personality, social interactions and environmental heterogeneity.Crossref | GoogleScholarGoogle Scholar | 23569291PubMed |

Moseby, K., and Read, J. (2001). Factors affecting pitfall capture rates of small ground vertebrates in arid South Australia. II. Optimum pitfall trapping effort. Wildlife Research 28, 61–71.
Factors affecting pitfall capture rates of small ground vertebrates in arid South Australia. II. Optimum pitfall trapping effort.Crossref | GoogleScholarGoogle Scholar |

Nersesian, C. L., Banks, P. B., and McArthur, C. (2011). Behavioural responses to indirect and direct predator cues by a mammalian herbivore, the common brushtail possum. Behavioral Ecology and Sociobiology 66, 47–55.
Behavioural responses to indirect and direct predator cues by a mammalian herbivore, the common brushtail possum.Crossref | GoogleScholarGoogle Scholar |

Norbury, G., Spencer, N., Webster, R., Bailey, J., Walker, R., Wilson, R., Hunter, M., and Reed, C. (2002). Best-practice trapping of ferret populations. Landcare Research Contract Report LC 1, 140.

Noss, A. J. (1999). Censusing rainforest game species with communal net hunts African Journal of Ecology 37, 1–11.
Censusing rainforest game species with communal net huntsCrossref | GoogleScholarGoogle Scholar |

NSW Department of Primary Industries (2020). ‘Use of pitfall traps.’ (NSW Department of Primary Industries.)

O’Farrell, M. J., Clark, W. A., Emmerson, F., Juarez, S. M., Kay, F. R., O’Farrell, T. M., and Goodlett, T. Y. (1994). Use of a mesh live trap for small mammals: are results from Sherman live traps deceptive? Journal of Mammalogy 75, 692–699.
Use of a mesh live trap for small mammals: are results from Sherman live traps deceptive?Crossref | GoogleScholarGoogle Scholar |

Pianka, E. R. (1971). Ecology of the agamid lizard Amphibolurus isolepis in Western Australia. Copeia , 527–536.
Ecology of the agamid lizard Amphibolurus isolepis in Western Australia.Crossref | GoogleScholarGoogle Scholar |

Pierce, C. L., Rasmussen, J. B., and Leggett, W. C. (1990). Sampling littoral fish with a seine: corrections for variable capture efficiency. Canadian Journal of Fisheries and Aquatic Sciences 47, 1004–1010.
Sampling littoral fish with a seine: corrections for variable capture efficiency.Crossref | GoogleScholarGoogle Scholar |

Prout, D., and King, C. (2006). The effect of handling under anaesthetic on the recapture rate of wild ship rats (Rattus rattus). Animal Welfare 15, 63.

Purdie, R. (1984). ‘Land systems of the Simpson Desert region.’ (CSIRO Publishing: Melbourne, Vic., Australia.)

Read, J., and Moseby, K. (2001). Factors affecting pitfall capture rates of small ground vertebrates in arid South Australia. I. The influence of weather and moon phase on capture rates of reptiles. Wildlife Research 28, 53–60.
Factors affecting pitfall capture rates of small ground vertebrates in arid South Australia. I. The influence of weather and moon phase on capture rates of reptiles.Crossref | GoogleScholarGoogle Scholar |

Réale, D., Reader, S. M., Sol, D., McDougall, P. T., and Dingemanse, N. J. (2007). Integrating animal temperament within ecology and evolution. Biological Reviews of the Cambridge Philosophical Society 82, 291–318.
Integrating animal temperament within ecology and evolution.Crossref | GoogleScholarGoogle Scholar | 17437562PubMed |

Rodda, G. H., Savidge, J. A., Tyrrell, C. L., Christy, M. T., and Ellingson, A. R. (2007). Size bias in visual searches and trapping of brown treesnakes on Guam. The Journal of Wildlife Management 71, 656–661.
Size bias in visual searches and trapping of brown treesnakes on Guam.Crossref | GoogleScholarGoogle Scholar |

Rolfe, J. K., and McKenzie, N. L. (2000). Comparison of methods used to capture herpetofauna: an example from the Carnarvon Basin. Records of the Western Australian Museum 61, 361–371.
Comparison of methods used to capture herpetofauna: an example from the Carnarvon Basin.Crossref | GoogleScholarGoogle Scholar |

Schirmer, A., Herde, A., Eccard, J. A., and Dammhahn, M. (2019). Individuals in space: personality-dependent space use, movement and microhabitat use facilitate individual spatial niche specialization. Oecologia 189, 647–660.
Individuals in space: personality-dependent space use, movement and microhabitat use facilitate individual spatial niche specialization.Crossref | GoogleScholarGoogle Scholar | 30826867PubMed |

Skalski, J. R. (1994). Estimating wildlife populations based on incomplete area surveys. Wildlife Society Bulletin (1973–2006) 22, 192–203.

Stokes, V. L. (2013). Trappability of introduced and native rodents in different trap types in coastal forests of south-eastern Australia. Australian Mammalogy 35, 49–53.
Trappability of introduced and native rodents in different trap types in coastal forests of south-eastern Australia.Crossref | GoogleScholarGoogle Scholar |

Thompson, G., and Withers, P. (2005). The relationship between size-free body shape and choice of retreat for Western Australian Ctenophorus (Agamidae) dragon lizards. Amphibia-Reptilia 26, 65–72.
The relationship between size-free body shape and choice of retreat for Western Australian Ctenophorus (Agamidae) dragon lizards.Crossref | GoogleScholarGoogle Scholar |

Walsh, R. N., and Cummins, R. A. (1976). The open-field test: a critical review. Psychological Bulletin 83, 482.
The open-field test: a critical review.Crossref | GoogleScholarGoogle Scholar | 17582919PubMed |

Walsh, M. G., Fenner, D. B., and Winkelman, D. L. (2002). Comparison of an electric seine and prepositioned area electrofishers for sampling stream fish communities. North American Journal of Fisheries Management 22, 77–85.
Comparison of an electric seine and prepositioned area electrofishers for sampling stream fish communities.Crossref | GoogleScholarGoogle Scholar |

Ward‐Fear, G., Rangers, B., Pearson, D., Bruton, M., and Shine, R. (2019). Sharper eyes see shyer lizards: collaboration with indigenous peoples can alter the outcomes of conservation research. Conservation Letters 12, e12643.
Sharper eyes see shyer lizards: collaboration with indigenous peoples can alter the outcomes of conservation research.Crossref | GoogleScholarGoogle Scholar |

Williams, D. F., and Braun, S. E. (1983). Comparison of pitfall and conventional traps for sampling small mammal populations. The Journal of Wildlife Management 47, 841–845.
Comparison of pitfall and conventional traps for sampling small mammal populations.Crossref | GoogleScholarGoogle Scholar |

Wilson, A. D. M., Binder, T. R., McGrath, K. P., Cooke, S. J., Godin, J.-G. J., and Kraft, C. (2011). Capture technique and fish personality: angling targets timid bluegill sunfish, Lepomis macrochirus. Canadian Journal of Fisheries and Aquatic Sciences 68, 749–757.
Capture technique and fish personality: angling targets timid bluegill sunfish, Lepomis macrochirus.Crossref | GoogleScholarGoogle Scholar |