H. J. A. Jensen, B. Weiner, J. V. Ortiz, and Y. Öhrn*, A Powerful Procedure for Optimizing AGP States, Int. J. Quant. Chem., Quant. Chem. Symp. 16, 615-31 (1982). Request reprint. DOI:10.1002/qua.560220853 .