1. On the influence of the condensor on the resolving powder of a microscope;Boltjes;Proc. Akad. Wetenschappen Amsterdam,1942
2. Some instances of tricomplex flocculation. I. Soybean phosphatide + carraghene + crystalloid cation;de Jong;Proc. Akad. Wetenschappen Amsterdam,1943
3. II. The flocculation of egglecithin and carraghene sols with crystalloid cations;de Jong;Proc. Akad. Wetenschappen Amsterdam,1943
4. III. The flocculation of gelatine + carraghene with alkali and earth alkali cations;de Jong;Proc. Akad. Wetenschappen Amsterdam,1943
5. L'influence des conditions de I'expérience sup le dosage chronométrique de la peroxydase;Derx;Proc. Akad. Wetenschappen Amsterdam,1942