1. Kaufmann MH: The Atlas of Mouse Development, p. 512. Academic Press, London, UK, 1992.
2. Kaufmann MH Bard JBL: The Anatomical Basis of Mouse Development, p. 291. Academic Press, San Diego, CA, 1999.
3. Rugh R: The Mouse: Its Reproduction and Development, p. 430. Oxford University Press, Oxford, UK.