J.G. Bannenberg and A. Tip: A calibration system for total-pressure gauges in the range 10-3-10-5 torrIn: Proceedings of the Fourth International Vacuum Congress Manchester, [s.n.], 1968. - pp. 609-612
A. Vermeer and A.A. Ravenstein, A method for the measurement of small shifts of the resonance frequency of a microwave cavity, J. Phys. E 1, 152-154 (1968)
J.F.M. Aarts, F.J. de Heer and D.A. Vroom, Emission cross sections of the first negative band system of N2 by electron impact, Physica 40, 197-206 (1968)