Orchideen von Neu-GuineaPublished in Repertorium novarum specierum regni vegetabilis, in 1911, in volume 9, issue 7-9, pages 97Revision der Orchidaceen von Deutsch-SamoaPublished in Repertorium novarum specierum regni vegetabilis, in 1911, in volume 9, issue 7-9, pages 98-112
Revision der Orchidaceen von Deutsch-SamoaPublished in Repertorium novarum specierum regni vegetabilis, in 1911, in volume 9, issue 7-9, pages 98-112