1. G. A. Jeffrey and W. Saenger, Hydrogen Bonding in Biological Structures, Springer, Berlin (1991).
2. W. Saenger, Principles of Nucleic Acid Structure [Russian translation], Mir, Moscow (1987).
3. N. K. Kochetkov, É. I. Budovskii, E. D. Sverdlov et al., Organic Chemistry of Nucleic Acids [in Russian], Khimiya, Moscow (1970).
4. J. Ladik, Quantum Biochemistry for Chemists and Biologists [Russian translation], Mir, Moscow (1974).
5. P. O. Löwdin, Ann. N. Y. Acad. Sci., 158, 86–95 (1969).