Ask for document about Root algorithms

Dear Root users,

I would like to ask you about document, which writes about algorithms used by ROOT (in particular, fitting method, how root calculate parameter errors, etc)

I write a program myself and want to compare to ROOT. For this reason, I need to be certain that ROOT and me use the same algorithms.

Thank you very much,

Regarding fitting, have you looked in the reference guides of the fitting classes themselves ? usually the algorithm used are described thereā€¦