Citations within the text should include the author's last name and year, for example [Cheeseman, 1985]. Append lower case letters to the year in cases of ambiguity. Multiple authors should be treated as in the following examples: [Abelson et al., 1985] and [Brachman and Schmolze, 1985]. If the author portion of a citation is obvious, it should be omitted, e.g., Levesque levesque:belief. Multiple citations should be collapsed as follows: [Levesque, 1984a,Levesque, 1984b].