Gosler, A. (1987). Sexual dimorphism in the summer bill-length of the Great Tit. Nederlandse Ornithologische Unie.
Lua i Stíl Chicago (17ú heag.)Gosler, A. Sexual Dimorphism in the Summer Bill-length of the Great Tit. Nederlandse Ornithologische Unie, 1987.
Lua MLA (9ú heag.)Gosler, A. Sexual Dimorphism in the Summer Bill-length of the Great Tit. Nederlandse Ornithologische Unie, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.