@article{Happel2002,
author = {Happel, S.K. and Hogan, T.D.},
title= {Counting snowbirds: The importance of and the problems with estimating seasonal populations},
year = {2002},
doi = {10.1023/A:1019560405310},
volume = {21},
number = {3},
pages = {227--240},
}