engert, m. (1964). classification of industries in social countries. the institute of national planning.
芝加哥风格引文engert, manfred. Classification of Industries in Social Countries. cairo: the institute of national planning, 1964.
MLA引文engert, manfred. Classification of Industries in Social Countries. the institute of national planning, 1964.
警告：这些引文格式不一定是100％准确.