@article{Pennycuick-2001-4927,
  author = {Pennycuick, C},
  title = {Speeds and Wingbeat Frequencies of Migrating Birds Compared with Calculated Benchmarks},
  journal = {Journal of Experimental Biology},
  year = {2001},
  month = {jul},
  publisher = {The Company of Biologists},
  volume = {204},
  pages = {3283--3294},
  url = {http://jeb.biologists.org/content/204/19/3283},
  keywords = {Birds, Passerines, Raptors},
}