REFERENCES FOR PROBLEMS
6. F. Sondheimer, Accts. Chm. Res., 5, 81 (1972).
12 and 13. A. Liberles, Introduction to Molecular Orbital Theory, Holt, Rinehart, and Win-
ston, New York, 1966; J. D. Roberts, Notes on Molecular Orbital Calculations, W. A.
Benjamin, Menlo Park, Calif., 1962.