Werke:
- Taxonomic results of the Bryotrop expedition to Zaire and Rwanda : 8., Riccia vulcanicola E. Fischer (subgenus Ricciella, Sectio Cavernosae), a new species from the Virunga Volcanoes, Rwanda
- Taxonomic results of the Bryotrop expedition to Zaire and Rwanda : 4., a preliminary check-list of the Hepaticae and Anthocerotae from Central Africa (Zaire, Rwanda, Burundi)
- Vegetation von Ruanda : zur Biodiversität und Ökologie eines zentralafrikanischen Landes
- Taxonomic results of the Bryotrop expedition to Zaire and Rwanda : 10., Trichocoleaceae, Geocalycaceae, Acrobolbaceae, Balantiopsidaceae, Lepidoziaceae (Telaranea, Arachniopsis), Calypogeiaceae,...