APA

United States, . (1981). Better monitoring techniques are needed to assess the quality of rivers and streams. [Washington, D.C: .

Chicago

United States, . 1981. Better monitoring techniques are needed to assess the quality of rivers and streams. [Washington, D.C: .

Harvard

United States, . (1981). Better monitoring techniques are needed to assess the quality of rivers and streams. [Washington, D.C: .

MLA

United States, . Better monitoring techniques are needed to assess the quality of rivers and streams. [Washington, D.C: . 1981.