Virginia Polytechnic Institute and State University. Dept. of Mining and Minerals Engineering & United States. Dept. of Energy. Mining Research and Development. (1981). Design optimization in underground coal systems: Final technical report as of February 28, 1981. U.S. Dept. of Energy, Assistant Secretary for Energy Technology, Division of Fossil Fuel Extraction, Mining Research and Development.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Virginia Polytechnic Institute and State University. Dept. of Mining and Minerals Engineering و United States. Dept. of Energy. Mining Research and Development. Design Optimization in Underground Coal Systems: Final Technical Report as of February 28, 1981. [Washington?]: U.S. Dept. of Energy, Assistant Secretary for Energy Technology, Division of Fossil Fuel Extraction, Mining Research and Development, 1981.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Virginia Polytechnic Institute and State University. Dept. of Mining and Minerals Engineering و United States. Dept. of Energy. Mining Research and Development. Design Optimization in Underground Coal Systems: Final Technical Report as of February 28, 1981. U.S. Dept. of Energy, Assistant Secretary for Energy Technology, Division of Fossil Fuel Extraction, Mining Research and Development, 1981.