M.  Schultz and Büdel, B., ?Key to the genera of the Lichinaceae?, The Lichenologist, vol. 34, pp. 39-62, 2002.

M.  Schultz, ?The saxicolous and terricolous, cyanobacterial lichens of Socotra (Yemen, Indian Ocean)?, Nova Hedwigia, vol. 77, pp. 73-97, 2003.

M.  Schultz and Büdel, B., ?On the systematic position of the lichen genus Heppia?, The Lichenologist, vol. 35, pp. 151-156, 2003.

M.  Schultz, ?On the identity of Anema dodgei, Psorotichia segregata and psorotichia squamulosa, three misunderstood cyanolichens from the southwestern United States?, The Bryologist, vol. 110, pp. 286-294, 2007.