I have or have read all the books that Rustie mentions and they are truely wonderful books. Especially Amuse-Bouche. I would say however, these books contain many recipes that are sort of canape sized and would make excellent pre-starters or entrees or indeed, hors d'oeuvres. You could of course make the recipes larger into a starter size portion.
Whilst Shane Osborns book is my favourite on the subject, I also have Appetizers, Starters and Hors d'oeuvres by Christine Ingram, Soups and starters by Linda Fraser and a real favourite is Australian Womens weekly, starters and soups.
All excellent but the Austalian Womens Weekly has the advantage of a picture with every recipe and a really good price tag.