At some point a short introduction to the basics of bundle methods is supposed to appear here.
For the moment, however, please consult the literature. For example:
- Jean-Baptiste Hiriart-Urruty und Claude Lemarechal; Convex Analysis and Minimization I, II; Springer, Berlin, 2nd edition 1996. ISBN 3-540-56860-6 (Volume I) and 3-540-56852-2 (Volume II).