1. Al-Gifri AN, Kürschner H, Mies B (1995) New records, additions and a new species, Sematophyllum socotrense Buck (Sematophyllaceae, Musci) to the bryophyte flora of Socotra (Yemen). Studies in Arabian bryophytes. 19. Nova Hedwigia 61:467–480
2. Andrus N, Trusty J, Santos-Guerra A, Jansen RK, Francisco-Ortega J (2004) Using molecular phylogenies to test phytogeographical links between East/South Africa–Southern Arabia and the Macaronesian islands – a review, and the case of Vierea and Pulicaria section Vieraeopsis (Asteraceae). Taxon 53:333–346
3. Anonymous (1924) Obituary notices of fellows deceased: Sir Isaac Bayley Balfour, 1853–1922. Philos R Soc Lond B, 96:i–xxxiv
4. Arvidsson L (1982) A monograph of the lichen genus Coccocarpia. Opera Bot 67:1–96
5. Baas P, Jansen S, Smets E (2001) Vegetative anatomy and affinities of Dirachma socotrana (Dirachmaceae). Syst Bot 26:231–241