H. Wachsmuth, A.J.H. Boerboom and H.A. Tasman, Calculation of the ion optical properties of inhomogeneous magnetic sector fields, Part 2: The second order aberrations outside the median plane, Z. Naturforsch. Teil A 14, 818-822 (1959)
T.J.M. Sluyters, E. de Haas and J. Kistemaker, Excitation functions in low pressure gases by ion impact measured by a grating monochromator overlapping the spectral range 1000 Å-6500 Å, Rev. Univers. Mines 9e serie 15, 264-266 (1959)
T.J.M. Sluyters, E. de Haas and J. Kistemaker, I. Charge exchange, ionization and electron loss cross-sections in the energy range 5 to 24 KeV, Physica 25, 1376-1388 (1959)