According to the bibliography of Peace Corps writers (referenced below) he has not published anything since then.
There are several ways to do a search for a person's publications. Google and Google Book are good starting points, but you also can benefit from looking in a few other places.
To establish copyright for a book first published in the US, an author or his/her publisher must deposit a copy of the work in the Library of Congress, and so you can check the Library of Congress Catalogue (reference below). Works copyrighted in the UK are deposited in multiple copyright libraries -- the easiest place to check is COPAC union catalogue, which now included the contacts of the British library.
Periodical indexing is more complicated. A reference librarian at your local public library can help you search various periodical indices to look for work by a specific author.
thanks. had already checked w/peace corps. it showed nothing. just curious as to what's become of stanley after all these years. we just celebrated the pc's 50th in dc. no one knows anything about his whereabouts.