Hanus, Michael Programming Logics, MPI for Informatics, Max Planck Society;
1-s2.0-0743106694900345-main.pdf (Verlagsversion), 4MB
Hanus, M. (1994). The Integration of Functions into Logic Programming: From Theory to Practice. The Journal of Logic Programming, 19 & 20, 583-628. doi:10.1016/0743-1066(94)90034-5.