"1988"^^ . "1988"^^ . . "Hekking, W. H. A. & Sipman, H. J. M. 1988. The lichens reported from the Guianas before 1987. Willdenowia, 17: 193-228." . "Hekking & Sipman (1988)" . . . "Hekking & Sipman (1988)" .