TITLE: Coordinate-free Calculus of Variations?
QUESTION [5 upvotes]: Lately I've been doing a lot of work related to solving variational problems (in the context of surface theory), and I'm getting really tired of going to local coordinates for everything.
So, I was wondering: does anyone know a good coordinate-free treatment for the calculus of variations?  I've heard such literature exists, but I can't say I'm familiar with it.
Any suggested reading you all may have would be much appreciated.
Thanks in advance,

REPLY [2 votes]: In case anyone else is curious, I've been getting some mileage out of Differential Geometry and the Calculus of Variations by Robert Hermann.
It's not exactly what I was looking for, but it's quite good, and I'm excited to apply some of the techniques in "Part 2" of the book.