Bibliografía (5 obras)
Species, age, and sex identification of ducks using wing plumage
1992
Preliminary keys to waterfowl age and sex identification by means of wing plumage
1984
Distribution of waterfowl species harvested in states and counties during 1971-80 hunting seasons
1983
Distribution in States and counties of waterfowl species harvested during 1961-70 hunting seasons
1975
Preliminary keys, age & sex of duck wings
1963