<sod>To demonstrate the concept, Knuth intentionally referred "Circular definition" and "Definition, circular" to each other in the index of ''[[The Art of Computer Programming]], Volume 1''.<eod>
<sod>To demonstrate the concept of [[recursion]], Knuth intentionally referred "Circular definition" and "Definition, circular" to each other in the index of ''[[The Art of Computer Programming]], Volume 1''.<eod>