1. see;Cieplak;Int J Quantum Chem Symp,1987
2. For the classical perturbation theory see for quantum systems see Modern Course in Statistical University of Texas Press Iuar issue spring of to be published;Zwanzig;Chem Phys Physics Int J Quantum Chem,1954
3. in Aduanced Theories and Approaches to the Electronic Structure of Molecules Dordrecht For more recent surveys see Academic San;Kelly;Int J Quantum Chem Advan Chern Phys Phys Rev Phys Lett J Quantum Chem Symp Chem Phys Chem Phys Lett Int J Quantum Chem Symp Bartlett Ann Rev Phys Chem Quantum Chem Quantum Chern Chem Phys Lett,1978
4. ungar particularly See alsc particularly and;Brillouin;Phys Radium Math Anz Wiss in Acta Vcilcidalensia J Quantum Chem Symp Phys Reu Proc Roy SOC ibid Math Phys Chem Phys Chem Phys Paldus Phys Rev,1932