Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L. and Thomas, L. (2001). Introduction to Distance Sampling: Estimating Abundance of Biological Populations, Oxford University Press, Oxford.
Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L. and Thomas, L. (2004). Advanced Distance Sampling: Estimating Abundance of Biological Populations, Oxford University Press, Oxford.