Authors: Defossez, René --- Broerse, Piet --- Denyn, J. --- Feremans, G. --- Henry, L. --- et al. Lerinckx, J. --- Meulemans, A. --- Nees, S. --- Rottiers, J. --- van den Broeck, P. --- Vos, F.
Publisher: [S.l.] [s.n.]