I'm trying to read the paper of Jost and Karcher on the existence of harmonic coordinates on a ball whose size only depend on the injectivity radius and a two sided bound on the curvature.


Unfortunately, my german skills are quite low and make the reading really slow. Does there exist another place to find this proof (in English or French) ?


Thanks



Harmonic coordinates on Riemannian manifolds
Perhaps [Jost's account of it](http://www.ams.org/mathscinet-getitem?mr=756629) from his lectures on harmonic mapppings between Riemannian manifolds contains a detailed description. 


There's also some related results due to [Hebey and Herzlich](http://www.ams.org/mathscinet-getitem?mr=1620864)


