1. Berck, K. H. (1961–1962): Beiträge zur Ethologie des Feldsperlings (Passer montanus) und dessen Beziehungen zum Haussperling (Passer domesticus). — Vogelwelt 1961, H. 5–6, p. 129–173; 1962, H. 1, p .8–25.
2. Boyd, A. W. (1934): Notes on the Tree-Sparrow. — Brit. Birds 25, p. 278–285.
3. — (1937): Notes on the Tree Sparrow — Ebenda 27, p. 259–260.
4. Creutz, G. (1949): Untersuchungen zur Brutbiologie des Feldsperlings (Passer m. montanus L.) — Zool. Jahrb. (Syst.) 78, p. 133–172.
5. Crook, J. H. (1960): Nest form and construction in certain West African Weaverbirds. — Ibis 102, p. 1–25.