T. Clark, J. Chandrasekhar, G. W. Spitznagel, and P. v. R. Schleyer, “Efficient diffuse function-augmented basis-sets for anion calculations. 3. The 3-21+G basis set for 1st-row elements, Li-F,” J. Comp. Chem., 4 (1983) 294-301. DOI: 10.1002/jcc.540040303
