Boulos, L. 2000: Boraginaceae in Loutfy Boulos Flora of Egypt vol. 2: 268-309. –Cairo, Egypt.
Feinbrun-Dothan, N. 1978: Boraginaceae in Flora Palaestina vol 3: 50-92. –Jerusalem.
Khatamsaz, M. 2002: Boraginaceae in Assadi et al. Flora of Iran no. 39. –Tehran.
Langstrom, E. 2002: Systematics of Echiochilon and Ogastemma (Boraginaceae) and the phylogeny of Boraginoideae. -Acta Univ. Ups. Comprehensive summaries of Uppsala Disserations from the Faculty of Science and Technology 633. 34 pp. -Uppsala.
Qaiser M. 1979: Boraginaceae in Jafri, S. M. H. and Gadi, A. EL. Flora of Libya no. 68 . -Al Faatech University, Faculty of Science, Department of Botany, Libya.
Riedl, H. 1967: Boraginaceae in K. H. Rechinger Flora Iranica no. 48. -Graz.
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