Ornithology

TURNER, L.M.

Washington, Government Printing Office, 1886.

COLLETT, ROBERT.

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LANGE, HALFDAN.

LØPPENTHIN, BERNT.

PETERSEN, ALWIN.

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TINBERGEN, NIKOLAAS.

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NAUMANN, J.A.

Gera-Untermhaus, (1899).

NAUMANN, J.A.

Gera-Untermhaus, (1902).

NAUMANN, J.A. - ENTEN.

Gera-Untermhaus, (1902).

MACKWORTH-PRAED, C.W. and GRANT, C.H.B.

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NAUMANN, J.A. - DROSSELN.

Gera-Untermhaus, 1905.

NAUMANN, J.A.

Gera-Untermhaus, (1897).

RINGMÆRKNINGERNE.

Kbhvn., 1931-63.

NAUMANN, J.A.

Gera-Untermhaus, (1902).

DANSK ZOOTOPOGRAFISK UNDERSØGELSE.

Kbhvn., 1937-67.

THE AUK.

Lancaster, PA., 1929-35.

NAUMANN, J.A.

Gera-Untermhaus, (1900).

GROSVENOR, GILBERT AND ALEXANDER WESTMORE. (EDTS.).

Washington, National Geographical Society, 1937).