1. Hayflick, L. (1965). Tex. Rep. Biol. Med. 23, Suppl. 1, 285–303.
2. MacPherson, I. (1966). J. Cell Sci. 1, 145–168.
3. Edward, D.G.ff. (1969). Progr. Immunobiol. Standard. 3, 17–22.
4. Stanbridge, E. (1971). Bacterial. Rev. 35, 206–227.
5. Barile, M.F. (1973). In: Contamination in Tisane Culture. Fogh, J. Ed. Academic Press, New York, pp. 131–172.