Ingpen, R., & Wilkinson, P. (1993). Encyclopedia of Ideas that Changed the World: The Greatest Discoveries and Inventions of Human History. Dragons World.
استشهاد بنمط شيكاغوIngpen, Robert, و Philip Wilkinson. Encyclopedia of Ideas That Changed the World: The Greatest Discoveries and Inventions of Human History. Limpsfield: Dragons World, 1993.
MLA استشهادIngpen, Robert, و Philip Wilkinson. Encyclopedia of Ideas That Changed the World: The Greatest Discoveries and Inventions of Human History. Dragons World, 1993.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.