He read books, memorized them, and then placed them upside down on the shelf to show that he had finished reading them, a practice he maintained all his life.
يقرأ الكتب، ويحفظه ، ثم يضعه رأسا على عقب على الرف لإظهار أنه قد انتهى قراءتها، وهي ممارسة الحفاظ طوال حياته.