1. Austin, C. R.: The mammalian egg. Oxford: Blackwell, 1961.
2. Bell, P. R.: Intranucleolar bodies with axial structure in the fern Pteridium. Chromosom (Berl.) 24, 188?193 (1968).
3. Bernhard, W.: Ultrastructural aspects of the normal and pathological nucleolus in mammalian cells. Nat. Cancer Inst. Monogr. 23, 13?38 (1966).
4. ?, Granboulan, N.: Electron microscopy of the nucleoli in vertebrate cells. In: Ultrastructure in biological systems. The nucleus (A. J. Dalton and F. Haguenau, eds.), p. 81. New York and London: Academic Press 1968.
5. Bolognari, A.: Ultrastructure of nucleoli in oocytes of Patella coetulea. Nature (Lond.) 183 1136 (1959).