H.J. Hopman, T. Matitti and J. Kistemaker, The electron cyclotron instability and high-frequency ionization in a beam-plasma experiment, Plasma Phys. 10, 1051-1067 (1968)
W.A. Oost, J.H. Los, A.N. van der Steege, A.J.H. Boerboom and A.E. de Vries, Measurement of relative diffusion coefficients and thermal diffusion factors of CO2 isotopes in Ar and He, Physica 36, 637-645 (1967)