K. R.  Apt, Gabbrielli, M., and Pedreschi, D., ?A Closer Look at Declarative Interpretations?, J. Log. Program., vol. 28, pp. 147-180, 1996.

K. R.  Apt and Pedreschi, D., ?Reasoning about Termination of Pure Prolog Programs?, Inf. Comput., vol. 106, pp. 109-157, 1993.

K. R.  Apt and Pedreschi, D., ?Proving Termination of General Prolog Programs?, in TACS, 1991, pp. 265-289.