1. Allenspach, A. L.: Ultrastructural observations of oesophageal organogenesis in the chick embryo. Abstract. J. Cell Biol. 43, 5a (1969).
2. Ballard, K. J.: Studies on the participation of hydrolytic enzymes in physiological autolysis in degenerating regions of the rat foetus. Ph. D. Thesis, University of London (1965).
3. Behnke, O.: Demonstration of acid phophatase containing granules and cytoplasmic bodies in the epithelium of foetal rat duodenum during certain stages of differentiation. J. Cell Biol. 18, 251–265 (1963).
4. Bellairs, R.: Cell death in chick embryos as studied by electron microscope. J. Anat. (Lond.) 95, 54–60 (1961).
5. Birks, R. I., Weldon, P. R.: Formation of crystalline ribosomal arrays in cultured chick embryo dorsal root ganglia. J. Anat. (Lond.) 109, 143–156 (1971).