Catéchisme illustré des vérités nécessaires, 12 images, ; 12 leçons, Paris (Procure générale de la Congrégation du Saint-Esprit, Oeuvre ; apostolique générale des missions) 1906, with translation by P. August ; Halbing in German and into the Duala language as preparation for a ; printed 1906; also contains: cover letter by Halbing

Contains among other things: Floating docks in Duala and Dar es Salaam Improvement of landing conditions in Swakopmund

Contains among other things: New construction of a storage shed Operation of the repair workshop and Duala

Contains among other things: Scales in Duala Coal procurement and supply