APA Style

WATER erosion: abridged proceedings of the international IHP/MAB symposium on water erosion, Varna, Bulgaria, 19-24 September 1988. (1989). : UNESCO.

MLA Style

WATER erosion: abridged proceedings of the international IHP/MAB symposium on water erosion, Varna, Bulgaria, 19-24 September 1988. . : UNESCO, 1989. Electronic resources.