In this case there is no need to indicate the issue number or month, since the article can be located by the page numbers alone.
Surname, Initials. "Title." Journal Name Volume Number (Year): Pages.
McLuhan, Marshall. "Pound, Eliot, and the Rhetoric of `The WasteLand.' " New Literary History 10 (1979): 557-579.
Dosman, Edgar J. "Hemispheric Relations in the 1980s: A Perspective from Canada." Journal of Canadian Studies 19.4 (1984): 42-60.
The volume number (19) and the issue number (4) are both given since each of the four issues of volume 19 has pages numbered 42 to 60.