1. Hollman KH: Cytology and fine structure of the mammary gland. In: Larson BL and Smith VR (ed). Lactation: a comprehensive treatise, Vol. 1, Academic Press, New York, 1974, pp 3?37
2. Dawson EK: A histological study of the normal mamma in relation to tumour growth. I. Early development to maturity. Edinburgh Med J 41: 653?682, 1934
3. Cole HA: The mammary gland of the mouse during the oestrus cycle, pregnacy and lactation. Proc Royal Soc London (Biol) 114: 136?161, 1933
4. Turner CV, Gomez ET: The normal development of the mammary gland of the male and female albino mouse. Mo Agric Station Res Bull 182: 3?20, 1933
5. Russo IH, Russo J: Developmental stage of the rat mammary gland as determinant of its susceptibility to 7,12 dimethylbenz[a]anthracene. J Natl Cancer Inst 61: 1439?1449, 1978