Reference for the Tortoise and Hare algorithm by Floyd? Can someone please point me to a book or paper that describes the Tortoise and Hare algorithm by Floyd? 

I know there are ample websites out there, but for reference purposes, I need a book or paper to point to.
Quoting Wikipedia:


  The algorithm is named after Robert W. Floyd, who was credited with
  its invention by Donald Knuth.3[4] However, the algorithm does not
  appear in Floyd's published work, and this may be a misattribution:
  Floyd describes algorithms for listing all simple cycles in a directed
  graph in a 1967 paper,[5] but this paper does not describe the
  cycle-finding problem in functional graphs that is the subject of this
  article. In fact, Knuth's statement (in 1969), attributing it to
  Floyd, without citation, is the first known appearance in print, and
  it thus may be a folk theorem, not attributable to a single
  individual.[6]


Now looking up reference [4], yields the Handbook of Applied Cryptography, which indeed contains a description as Note 3.8 (PDF version). However the Handbook also attributes the algorithm to Knuth as Wikipedia does, so 


  Knuth, Donald E. (1969), The Art of Computer Programming, vol. II:
  Seminumerical Algorithms, Addison-Wesley, p. 7, exercise 6


is the reference you are looking for with the Handbook citing it as (PDF, reference 692)


  D.E.Knuth , The Art of Computer Programming – Seminumerical
  Algorithms, volume 2, Addison-Wesley, Reading, Massachusetts, 2nd
  edition, 1981