1. Bunge, R., M. Bunge, E. Peterson, and M. Murray: Ultrastructural similarities between in vitro and in vivo central nervous tissue. Abstracts Third Annual Meeting American Society for Sell Biology. J. Cell Biol. 19, 11 a (1963).
2. De Robertis, E.: Submicroscopic morphology and function of the synapse. Exp. Cell Res., Suppl. 5, 347?369 (1958).
3. De Robertis, E., and H. S. Bennett: Some features of the submicroscopic morphology of synapses in frog and earthworm. J. biophys. biochem. Cytol. 1. 47?58 (1955).
4. Gray, E. G.: Electron microscopy of synaptic organelles of the central nervous system. Internat. Congr. of Neuropathology. II. Thema II and III, p. 57?61 (1961).
5. Hild, W.: Myelogenesis in cultures of mammalian central nervous tissue. Z. Zellforsch. 46, 71?95 (1957).