Barnet Sylvan, & Bedau Hugo. (2008). Current Issues and Enduring Questions: A Guide to Critical Thinking and Argument, with Readings (Tái bản lần thứ 8.). U.S.A: MC Graw Hill.

Barnet Sylvan, و Bedau Hugo. Current Issues and Enduring Questions: A Guide to Critical Thinking and Argument, With Readings. Tái bản lần thứ 8. U.S.A: MC Graw Hill, 2008.

Barnet Sylvan, و Bedau Hugo. Current Issues and Enduring Questions: A Guide to Critical Thinking and Argument, With Readings. Tái bản lần thứ 8. U.S.A: MC Graw Hill, 2008.