Amsterdam, s.e., 1947, in-8°, 249 pp + 223 b/w ills. h.t., sewn, orig. wrappers. Doctoral thesis at the University of Amsterdam, with a summary in French.
4. Amsterdam, Balkema, 1947, in-8°, 249 pp, 224 bw ills h.t., blue cloth, orig.wrapper preserved.