Butler-Bowdon, T., & Pratt, S. (2013). 50 philosophy classics: Thinking, being, acting, seeing, profound insights and powerful thinking from fifty key books (Unabridged.). Ascent Audio.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Butler-Bowdon, Tom, و Sean Pratt. 50 Philosophy Classics: Thinking, Being, Acting, Seeing, Profound Insights and Powerful Thinking from Fifty Key Books. Unabridged. Rego Park: Ascent Audio, 2013.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Butler-Bowdon, Tom, و Sean Pratt. 50 Philosophy Classics: Thinking, Being, Acting, Seeing, Profound Insights and Powerful Thinking from Fifty Key Books. Unabridged. Ascent Audio, 2013.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.