I. Sakho. (2010). Modified Atomic Orbital Calculations for $(1s,nl)^3L^{\pi}$ and $_2 (1,0)_n^{±1,3}S^e$ Excited States of He Isoelectronic Sequence. Journal of Atomic and Molecular Sciences. 1 (3). 224-242. doi:10.4208/jams.042710.051510a