REFERENCES
- AMADON , D. 1959 . Remarks on the subspecies of grass owl, Tyto capensis. . J. Bombay Nat. Hist. Soc. , 56 : 344 – 346 .
- BEAUFORT , L. F. DE . 1951 . Zoogeography of the land and inland waters London. Sidgwick and Jackson
- CHAPIN , J. P. 1939 . The birds of the Belgian Congo. II. . Bull. Am. Mus. Nat. Hist. , 75 : 1 – 632 .
- COLBERT , E. H. 1935 . Siwalik mammals in the American Museum of Natural History. . Trans. Am. Philos. Soc. Philadelphia. New Series , 26 : 1 – 401 .
- DARLINGTON , P. J. 1957 . Zoogeography New York. John Wiley
- HALL , B. P. and MOREAU , R. E. 1962 . A study of the rare birds of Africa. . Bull. Brit. Mus. (Nat. Hist.). Zoology. , 8 : 313 – 378 .
- LÖNNBERG , E. 1929 . The development and distribution of the African fauna in connection with and depending upon climatic changes. . Ark. Zool. , 21A ( 4 ) : 1 – 32 .
- MEES , G. F. 1964 . A revision of the Australian owls (Strigidae and Tytonidae). . Zool. Verhand. (Rijksmus Nat. Hist. Leiden). , 65 : 1 – 62 .
- MEINERTZHAGEN , R. 1951 . Some relationships between African, Oriental, and Palaearctic genera and species, with a review of the genus Monticola. . Ibis. , 93 : 443 – 459 .
- MOREAU , R. E. 1952 . Africa since the Mesozoic: with particular reference to certain biological problems. . Proc. Zool. Soc. London. , 121 : 869 – 913 .
- MOREAU , R. E. 1963 . Vicissitudes of the African biomes in the late pleistocene. . Proc. Zool. Soc. London. , 141 ( 2 ) : 395 – 421 .
- STRESEMANN , E. and GROTE , H. 1926 . Verbreitung und Gliederung afrikanischer Formenkreise. . Verh. VI. Int. Orn. Congr. Copenhagen , : 358 – 374 .
- VOOUS , K. H. 1964 . Wood owls of the genera Strix and Ciccaba. . Zool. Meded. (Rijksmus. Nat. Hist. Leiden.) , 39 : 471 – 478 .