Electron-Impact Ionization Cross Sections for Polyatomic Molecules, Radicals, and Ions
   Y. Kim, K.K.Irikura American Institute of Physics, 2000

Electron-Impact Ionization Cross Sections Of Atmospheric Molecules
   W.Hwang, N.Weinberger, M.Ali, M.Rudd American Institute of Physics, 1997

Quantum Mechanically Complete Measurements In Electron Impact Excitation Of Helim
   A.G.Mikosza, American Institute of Physics, 2000

TOPbase/TIPbase
   C.Mendoza, Physics Center, (IVIC), 2000