@book{21,
  keywords = {Atlas},
  author = {Asher Jim and Warren Martin S. and Fox Richard and Harding Paul T. and Jeffcoate G. and Jeffcoate S.},
  title = {The millennium atlas of butterflies in Britain and Ireland},
  year = {2001},
  publisher = {Oxford University Press},
  address = {Oxford},
  language = {eng},
}