A useful link. http://www.hirsutum.info/rhododendron/hybrids/index.php?start=A
For those that are not familiar with it, Hirsutum.info is part of a very ambitious project to publish listings, descriptions and photographs of all rhododendrons and azaleas.
The name comes from Rhododendron hirsutum which was the first rhododendron to be classified and named.
Here is a link that might be useful: Hirsutum rhododendron project