1. King M (1990) Amphibia. In: Animal cytogenetics, vol 4/2. pp 1–241, John B (ed), Gebrüder Borntraeger, Stuttgart
2. Schmid M (1983) Evolution of sex chromosomes and heterogametic systems in Amphibia. Differentiation 23 (Suppl): 13–22
3. Schmid M and Haaf T (1989) Origin and evolution of sex chromosomes in Amphibia: The cytogenetic data. In: Evolutionary mechanisms in sex determination, pp 37–56, Wachtel SS (ed), CRC Press, Boca Raton
4. Schmid M, Nanda I, Steinlein C, Kausch K, Haaf T and Epplen JT (1991) Sex-determining mechanisms and sex chromosomes in Amphibia. In: Amphibian cytogenetics and evolution, pp 393–430, Green DM, Sessions SK (eds), Academic Press, San Diego
5. Singh L (1974) Present status of sex chromosomes in amphibians. Nucleus 17: 17–27