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2. Andersen, J. B. (1978): Formodet gråspurv x skokspurv (Passer domesticus andP. montanus) hybrid. Dansk Orn. Foren. Tidsskr. 72: 143–144.
3. Anderson, T. R. (1978): Population studies of European Sparrows in North America. Occas. Pap. Univ. Kans. Mus. Nat. Hist. 70: 1–58.
4. Arnott, J. (1981): Fair Isle Bird Observ. Rep. 33: 59.
5. Ash, J. S., &P. Colston (1981): A House x Somali SparrowPasser domesticus x.P. castanopterus hybrid. Bull. Brit. Orn. Cl. 100: 291–294.