There is a book called American and British Poetry: A Guide to the Criticism, 1925-1978, which was compiled by Harriet Semmes Alexander and published in 1984. It is a 2 volume book. Sylvia Plath is covered on pages 298-303. What this bibliography does is list works by Plath, and then gives citations of essays that discuss or mention the work. Of course, it only goes to 1978, so it is "older", but nevertheless I think it is an interesting reference tool. I don't think it's nearly complete either - based on what I've seen published before 1978, it seems skinny. But, it's a cool resources nonetheless. As the title indicates, it is only looking at Plath's poetry. Funnily enough, "Three Women" is not listed under "Three Women", but under "Poem for Three Voices."
If your local town or college library doesn't have it - no worries. Google does!
If your local town or college library doesn't have it - no worries. Google does!