Simulation models, GIS and nonpoint-source pollution :
January 1991 - December 1993 /
Joe Makuch and Bonnie Emmert.

APA Citation

Makuch, J., Emmert, B., National Agricultural Library (U.S.). (1994). Simulation models, GIS and nonpoint-source pollution: January 1991 - December 1993. Beltsville, Md.: National Agricultural Library.

MLA Citation

Makuch, Joe, Bonnie Emmert, and National Agricultural Library (U.S.). Simulation Models, GIS And Nonpoint-source Pollution: January 1991 - December 1993. Beltsville, Md.: National Agricultural Library, 1994.

Warning: These citations may not always be complete (especially for serials).