Mazur, Grzegorz, Marcin Makowski, Jakub Sumera, and Krzysztof Kowalczyk. 2012. “Efficient Energy and Electrostatic Properties Calculations at the MP2 Theory Level: A Case Study of Density Matrix-Based Computational Quantum Chemistry”. COMPUTING AND INFORMATICS 31 (3):665-73. https://www.cai.sk/ojs/index.php/cai/article/view/1013.