1. Berry Paul C. SHARP APL Reference Manual I.P. Sharp Associates 1979. Berry Paul C. SHARP APL Reference Manual I.P. Sharp Associates 1979.
2. Graham Ronald L. Donald E. Knuth Oren Patashnik Concrete Mathematics Addison-Wesley 1989. Graham Ronald L. Donald E. Knuth Oren Patashnik Concrete Mathematics Addison-Wesley 1989.
3. Hui Roger K.W. Algorithm 135: Generating the Group Table ofS(n) APL Quote-Quad 10.1 1979 9. Hui Roger K.W. Algorithm 135: Generating the Group Table ofS(n) APL Quote-Quad 10.1 1979 9.