1. W. G. Chinn and N. E. Steenrod, “First Concepts of Topology” Random House, 1966.
2. W. B. Temple, Makromol. Chem., 160, 277 (1972).
3. O. Ore, “Graphs and their Uses”, Random House, 1963.
4. D. McLachlan, Jr., “X-Ray Crystal Structure”, McGraw Hill, 1957.
5. F. A. Cotton, “Chemical Applications of Group Theory”, 2nd Ed., Wiley Interscience, 1971.