"Differential electronic-excitation cross sections of molecular oxygen 
 by electron impact: The a ¹Delta_g and b ¹Sigma_g states" 
 Tong W. Shyn and Christopher J. Sweeney
 Phys. Rev. A, Vol 47, No 2, 1006 (1993)

"Differential electronic-excitation cross sections of molecular oxygen by electron impact: The a 1Deltag and b 1Sigmag states" Tong W. Shyn and Christopher J. Sweeney Phys. Rev. A, Vol 47, No 2, 1006 (1993)

"Differential electronic-excitation cross sections of molecular oxygen by electron impact: The a ¹Delta_g and b ¹Sigma_g states" Tong W. Shyn and Christopher J. Sweeney Phys. Rev. A, Vol 47, No 2, 1006 (1993)