TITLE: literature on geometrical viewpoint on calculus of variations for physics
QUESTION [5 upvotes]: What is a good reference for a geometrical viewpoint on the calculus of variations for physics, using differential forms etc. to derive Yang-Mills equations and other topics of the standard model?
Thanks for ideas.

REPLY [4 votes]: I think that the book 

David Bleecker: Gauge Theory and Variational Principles, Addison-Wesley, 1981

contains exactly what you are looking for.