Hydrological maps :
a contribution to the International Hydrological Decade.
APA Citation
World Meteorological Organization., Unesco. (1977). Hydrological maps: a contribution to the International Hydrological Decade. Paris: UNESCO.
MLA Citation
World Meteorological Organization, and Unesco. Hydrological Maps: a Contribution to the International Hydrological Decade. Paris: UNESCO, 1977.
Warning: These citations may not always be complete (especially for serials).