Published in Verslagen en mededeelingen der Koninklijke Akademie van Wetenschappen, in 1868, in volume 2, pages 307-314
Created: 2012-10-02, modified: 2012-10-02
Published in Versl. & Meded. Ak. Wet. Amsterd., in 1868, in volume 3, pages 80-85
Created: 2012-10-02, modified: 2012-10-02