Snake Society - Publication covers a wide variety of species and is in English and Dutch. Many older articles are available as PDF files. They also offer the publication as a subscription so you can get the latest issues.

Understanding Reptile Parasites - A very good book explaining the various parasites and medications used to treat them. If you're going to work with wild caught reptiles in particular you'll really need to understand the material in this book.

Rare Genetics - Offering DNA sexing and other genetic tests for reptiles. 

Older books available on open library:
Some of these books are quite old, so keep in mind that some recommendations may no longer be considered best practice, but generally even older books contain something useful in them.
I recommend searching for Chirs Mattison, Richard D. Bartlett, and Philippe de Vosjoli.