1. B. Uvnäs, Fedn Proc.33, 2172 (1974).
2. D. Lugunoff, J. Cell Biol.57, 252 (1973).
3. H. Harris,Cell Fusion (Clarendon Press, Oxford, 1970).
4. B. Ephrussi,Hybridization of Somatic Cells (Princeton, Univ. Press, Princeton 1972).
5. K. Sugiyama, Jap. J. Pharmac.21, 209 (1971).