There are very good IFR interactive courses at AOPA Air Safety Foundation
Interactive Safety Courses
An excellent book, a must for every instrument pilot is "The Instrument Flight Training Manual" from Peter Dogan (ISBN 0-916413-02-0)
Get also "Rod Machado's Instrument Pilot's Survival Manual"
And, the "Air Force Instrument Flying Manual" reprinted and published by Airguide Publications
Check also, and become a member of PPL/IR Europe for exchanging knowledge and experience about instrument flying. Resources, forums & more:
PPL/IR Europe
By the way, you are absolutely correct, and show good airmanship, in your search of books and other learning material. Instrument flying is something to continually think about, review and learn. Keep also in mind that there are very few good or competent "instrument" flight instructors. Good luck. Happy & Safe Flying,