| Reference Label | Details |
|---|---|
| note unc | The quoted uncertainty appeared to correspond to one std dev. and was multiplied by 2 to come closer to the desired 95% confidence limit |
| Drake 1988 | G. W. F. Drake, Can. J. Phys. 66, 586611 (1988) Theoretical Energies for the n=1 and 2 States of the Helium Isoelectronic Sequence up to Z=100 |