Ab initio calculations of energy transfer and non-additivity in the He-Ne laser systemA. S. Shalabi, M. M. Assem, S. Abd El-Aal, M. A. Kamel and M. M. Abd El-RahmanEur. Phys. J. D, 7 2 (1999) 181-189DOI: https://doi.org/10.1007/s100530050364