Boissier, E. 1875: Crucianella in Flora Orientalis, 3: 19-25. –Genevae & Basileae.
Ehrendorfer, F. 1982: Crucianella in P. H. Davis (ed.), Flora of Turkey. vol. 7: 725-733. -Edinburgh.
Ehrendorfer, F. and Schönbeck-Temesy, E. 1980: Rubiaceae in C.C. Townsend (ed.). Flora of Iraq, vol. 4: 564-628. -Baghdad.
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