Fish and Wildlife Information Exchange. Mariana Mallard, ESIS101048 draft. Virginia Tech University. 1996 [2020-12-22]. (HTML 原始内容 请检查|url=值 (帮助)存档于2000-01-19).
Fish and Wildlife Information Exchange. Mariana Mallard, ESIS101048 draft. Virginia Tech University. 1996 [2020-12-22]. (HTML 原始内容 请检查|url=值 (帮助)存档于2000-01-19).