Washington (State). Division of Geology and Earth Resources, Association of Engineering Geologists. Washington State Section, & Galster, R. W. (1989). Engineering geology in Washington. Washington State Dept. of Natural Resources, Division of Geology and Earth Resources.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Washington (State). Division of Geology and Earth Resources, Association of Engineering Geologists. Washington State Section, و Richard W. Galster. Engineering Geology in Washington. [Olympia, WA] (Mail Stop PY-12, Olympia 98504): Washington State Dept. of Natural Resources, Division of Geology and Earth Resources, 1989.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Washington (State). Division of Geology and Earth Resources, et al. Engineering Geology in Washington. Washington State Dept. of Natural Resources, Division of Geology and Earth Resources, 1989.