Ryszard Wojnecki Piotr Modrak Calculation of Two-center Integrals Between Slater-type Orbitals. 287-290 1993 17 Comput. Chem. 3 https://doi.org/10.1016/0097-8485(93)80009-3 https://www.wikidata.org/entity/Q127857998 db/journals/candc/candc17.html#WojneckiM93