Making b el nap's "useful four-valued logic" useful

In 1977 Nuel Belnap published two articles, "How a Computer Should Think" and "A Useful Four-Valued Logic", in which he defined a four-valued logic called F D E (First Degree Entailment). However, F D E does not allow entailments within statements, and no conditional connective is defined. As such, it is not really computationally "useful". This paper proposes conditional connectives to add to F D E, and describes the implementation of a reasoning tool for F D E with a conditional connective, with experimental results. With the addition of a conditional connective F D E starts to become truly computationally useful.