Closing the P Cycle

Curth-van Middelkoop, J. C. (Speaker), Regelink, I. C. (Contributor), H.H. Luesink (Contributor), C.P.A. van Wagenberg (Contributor), A. Greijdanus (Contributor), de Vries, W. (Contributor), J. Kros (Contributor), W. van Dijk (Speaker)