Gaya APA

Randall, L. (2011). Knocking on Heaven's Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World . United States of America: Harper-Collins.

Gaya MLA

Randall, Lisa. "Knocking on Heaven's Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World". United States of America: Harper-Collins, 2011. Text.