H.M.E. Schürmann, A.H.W. Aten, A.J.H. Boerboom, A.C.W.C. Bot, G. Couwenberg, D.F. Dance, P.M. Hurley, D. Ledent, H. Stauffer, J.J.S. Steensma and R. Suringa, Fourth preliminary note on age determinations of magnetic rocks by means of radioactivity, Geol. Mijnb. 39, 93-104 (1960)
H.A. Tasman, A.J.H. Boerboom and H. Wachsmuth, Calculation of the ion optical properties of inhomogeneous magnetic sector fields: Note on the trajectories outside the median plane with oblique incidence, and on the second order angular aberration coefficient, Z. Naturforsch. Teil A 15, 78-79 (1960)
