Citation
Austin, G.E., Musgrove, A.J., Rehfisch, M.M. & Armitage, M.J.S. 2002. An objective method of quantifying the avian interest of an area by means of a weighted population index. Wader Study Group Bulletin 99: 63. doi:http://www.waderstudygroup.org/pubs/wsgbull/content.php