1. Pilar F. L., Elementary Quantum Chemistry, McGraw-Hill, New York 1990, ISBN 978-007-050-093-8 .
2. Ed. J. Grotendorst, Modern Methods and Algorithms of Quantum Chemistry, vol. 3, Juelich: NIC Series 2000 (http://www2.fz-juelich.de/nic-series/Volume1/Volume1.html)