Coxhead, I. A. (1991). Environmental specific rates and biases of technical change in agriculture. s.n.
芝加哥风格引文Coxhead, Ian A. Environmental Specific Rates and Biases of Technical Change in Agriculture. [S.l: s.n, 1991.
MLA引文Coxhead, Ian A. Environmental Specific Rates and Biases of Technical Change in Agriculture. s.n, 1991.
警告：这些引文格式不一定是100％准确.