| APA | Smart Define. (1970). hydrological operational multipurpose subprogram thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/hydrological_operational_multipurpose_subprogram/thesaurus/broader |
| Chicago | Smart Define. 1970. "hydrological operational multipurpose subprogram thesaurus" https://smartdefine.org/hydrological_operational_multipurpose_subprogram/thesaurus/broader (accessed September 21, 2026). |
| Harvard | Smart Define 1970, hydrological operational multipurpose subprogram thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/hydrological_operational_multipurpose_subprogram/thesaurus/broader>. |
| MLA | Smart Define. "hydrological operational multipurpose subprogram thesaurus" 1 January 1970. Web. 21 September 2026. <https://smartdefine.org/hydrological_operational_multipurpose_subprogram/thesaurus/broader> |