Roper, L. D. (1976). Where have all the metals gone? University Publications.
芝加哥风格引文Roper, L. David. Where Have All the Metals Gone? Blacksburg, Va.: University Publications, 1976.
MLA引文Roper, L. David. Where Have All the Metals Gone? University Publications, 1976.
警告：这些引文格式不一定是100％准确.