The lichen flora of the Chagos Archipelago, including a comparison with other island and coastal tropical floras
Results of a botanical expedition to Mount Roraima, Guyana. II. Lichens
Looking back on 15 years of research on bioindication with Jan-Peter Frahm in Bonn
Foliicolous lichens and their lichenicolous fungi collected during the Smithsonian International Cryptogamic Expedition to Guyana 1996
La microscopia electronica aplicada al estudio de los liquenes en Venezuela