Report on the U.S. Geological Survey's evaluation program for standard reference samples distributed in April 1992 [microform] : T-119 (trace constituents), M-122 (major constituents), N-34 (nutrients), N-35 (nutrients), Hg-14 (mercury) / by H. Keith Long and Jerry W. Farrar (Open-file report ; 92-164)
Report on the U.S. Geological Survey's evaluation program for standard reference samples distributed in April 1992 [microform] : T-119 (trace constituents), M-122 (major constituents), N-34 (nutrients), N-35 (nutrients), Hg-14 (mercury) / by H. Keith Long and Jerry W. Farrar