1941 [8], 91 p., 13 figures, 2 plates, paperbound (original covers). Thesis.
Zaandam, Sombeek & zoon 1898 121 + [iii] pp., 24cm., rug licht hersteld, Academisch proefschrift [Universiteit van Amsterdam, 1898, Doctoral dissertation]
1941 [8], 91 p., 13 figures, 2 plates, paperbound. Thesis. Library stamps and markings.
1934 224 p., 2 figs, 5 pls, 3 maps, paperbound. Mainly on foraminifera. Thesis.