P. Linden S.J., Katekismus a katolik nyn boso nisadi na bwambo ba Duala (Cameroon); Limburg 1913[Library No. 1728 1914; Contains:; N.151-15: Manuscript in bound booklet, 1912; N.151-16Typed copy with envelope of the Spamersche Buchdruckerei in Leipzig, sent to P. Halbing on July 24, 1914, then handwritten note by P. Halbing: "up to page 37 proofs corrected to Lome Druckerei returned before the outbreak of the war, since nothing more heard, 5.11.[19]14".

[Kalat'a Evangelo na Epistel, 158 pages, Leipzig 1914. - Library No. 1731] 1914; Contains: Typed copy with envelope of the Spamersche Buchdruckerei in Leipzig, sent to P. Halbing on 30 July 1914, handwritten note by P. Halbing: "Gesanguch für die Christen in Kamerun in der Dualasprache".