Three titles in German in 5 volumes: (1) Nord-Sumatra.

Bericht über eine im Auftrag der Humboldt-Stiftung der Königlich Preussischen Akademie der Wissenschaften zu Berlin in den Jahren 1904-1906 ausgeführte Forschungsreise von Professor Dr. Wilhelm Volz. Band I. Die Batakländer. Band II. Die Gajoländer. Berlin, D. Reimer (E. Vohsen), 1909/ 1912, 2 volumes, XX,(4),395,(1) ; XIX,(5),428 p., with 5 (folding) coloured maps loose in envelopes on inside back board and with many plates and illustrations, original uniform cloth, 4to.

Spines with label and some wear to ends, corners slightly bumped. Good copy with ex libris of C.L. van Balen on the insides of both front boards; (2) Quer durch Borneo. Ergebnisse seiner Reisen in den Jahren 1894, 1896-97 und 1898-1900 von Dr. A.W. Nieuwenhuis. Leiden, E.J. Brill, 1904/ 1907, 2 volumes, XV,(1),493,(2); XIII,(1),557,(2) p., with large folding map and many (folding) (coloured) plates, original uniform gilt and decorated cloth, large 4to (very good copy); (3) Sunda. Eine Reise durch Sumatra von Martin Borrmann. Frankfurt am Main, Societäts-Druckerei G.M.B.H., 1925, 364,(2) p., with pasted plates, original cloth with dust jacket, 4to (dust jacket slightly damaged/ with small tears and some staining) (total 3 titles in 5 volumes).