I listed several of Thomas Erl’s books in my SOA Recommended reading list. A full list of Thomas Erl’s series of SOA books can be found here. Anyone working in the SOA space, regardless of vendor or technology stack, should read these books.
I found the “SOA Design Patterns” book and “Web Service Contract Design & Versioning for SOA” books to be the most helpful. Some of the other ones are a bit dry and long winded.