Ballard, E. G. (1971). Philosophy at the crossroads. Louisiana State University Press.
芝加哥风格引文Ballard, Edward G. Philosophy at the Crossroads. Baton Rouge: Louisiana State University Press, 1971.
MLA引文Ballard, Edward G. Philosophy at the Crossroads. Louisiana State University Press, 1971.
警告：这些引文格式不一定是100％准确.