1. The New Book of Prime Number Records. P. Ribenboim. Springer.
  2. Unsolved Problems in Number Theory. R. K. Guy. Springer-Verlag.
    2nd Ed.
  3. Factorization & primality testing. D. M. Bressoud. Springer-Verlag.
  4. Prime numbers and computer methods for factorization. H. Riesel. Birkhäuser.
  5. Recreations in the theory of numbers. Albert H. Beiler. Dover.
  6. Mathematical mysteries. Calvin C. Clawson. Perseus
  7. Excursions in number theory. C. S. Ogilvy & J. T. Anderson. Dover.
  8. Exploring number theory with microcomputers. D. D. Spencer. Camelot.