This integral drives has been obtained from the NWChem Software Packackge: https://github.com/nwchemgit/nwchem The goal of this project is to generate more structure and readability in the code and make it faster. The latter is achieved by rewriting code to modern Fortran (2008), use of co-array Fortran (CAT) and other techniques.

Sources:

Molecular Electronic‐Structure Theory Author(s):Trygve Helgaker, Poul Jørgensen, Jeppe Olsen First published:11 August 2000 Print ISBN:9780471967552 |Online ISBN:9781119019572 |DOI:10.1002/9781119019572 Copyright © 2000 John Wiley & Sons, Ltd

Modern Quantum Chemistry: Introduction to Advanced Electronic Structure Theory Paperback – 2 juli 1996 by Szabo and Ostlund.