Bruce's books cover the mathamatics and will give you much of the thinking behind the way an algorithm works. I would suggest that without a solid first year uni level comprehension of mathematics and the calculus, his books will loose you.
Buhlmann's work is in the public domain.
Second the recommendation for Mark Powell's excellent work.
You might also do a google search for V-Planner software (an implementation of VPM) and poke aound there. There are a couple of interesting essays which may help. Also, I believe there are several subscribers here -- including Ross Hemmingway who wrote V-Planner -- who may be able to walk you through the nuts and bolts.
However, if it's implementation that you are interested in finding out more about, then Mark's book is excellent.
