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W. H. A.  Hekking and Sipman, H. J. M., ?The Lichens Reported from the Guianas before 1987?, Willdenowia, vol. 17, pp. 193-228, 1988.

H. J. M.  Sipman and Raus, T., ?A Lichenological Comparison of the Paros and Santorini Island Groups (Aegean, Greece), with Annotated Checklist?, Willdenowia, vol. 29, pp. 239-297, 1999.

H. J. M.  Sipman and Raus, T., ?An Inventory of the Lichen Flora of kalimnos and Parts of Kos (Dodecanisos, Greece)?, Willdenowia, vol. 32, pp. 351-392, 2002.

H. J. M.  Sipman, ?The Lichens of Mainland Yemen?, Willdenowia, vol. 32, pp. 127-135, 2002.

M. Haji Moniri and Sipman, H. J. M., ?Lichens of two nature reserves in NE Iran?, Willdenowia, vol. 39, pp. 199-202, 2009.

D.  Killmann and Fischer, E., ?New Records for the Lichen Flora of Rwanda, East Africa?, Willdenowia, vol. 35, pp. 193-204, 2005.