1. Zuckerkandl, E., and Pauling, L., in Evolving Genes and Proteins (edit. by Bryson, V. and Vogel, H. J.), 97 (Academic Press, New York, 1965).
2. Fitch, W. M., and Margoliash, E., Science, 155, 279 (1967).
3. Dayhoff, M. O., Atlas of Protein Sequence and Structure, 4, (National Biomedical Research Foundation, Silver Spring, 1969).
4. Smith, E. L., in Homologous Enzymes and Biochemical Evolution (edit. by van Thoai, N. and Roche, J.), 43 (Gordon and Breach, New York, 1968).
5. Blomback, B., Blomback, M., Grondahl, N. J., and Holmberg, E., Archiv. Kemi, 25, 411 (1966).