@article {28700,
	title = {Classical calculations and the threshold electron-impact ionization of helium},
	journal = {International Journal of Mass Spectrometry and Ion Physics},
	volume = {2},
	year = {1969},
	pages = {414 - 416},
	issn = {0020-7381},
	doi = {https://doi.org/10.1016/0020-7381(69)80038-0},
	url = {http://www.sciencedirect.com/science/article/pii/0020738169800380},
	author = {Brion, C. E. and Thomas, G. E.}
}
