Machine translation has often been conceived as consisting of three steps: analysis of source-language sentence, transformation of analyzed pieces, and synthesis of target-language sentence. This paper is concerned with one aspect of the last step, namely, the rules of behavior of English articles. Since the classical definitions of definite and indefinite articles are operationally imprecise, proper mechanistic rules must be formulated in order to permit the automatic insertion or non-insertion of English articles. The rules discussed are of syntactic origin; however, note is also taken of their semantic aspects. This paper describes the methods used to derive these rules and offers ideas for further research.