I am interested in reading original work of some authors of theorems or concepts in mathematics because I believe that there is also an educational value to this and it might help me understand better those concepts because I can see where and how they came from from the author's minds.
For example I would be really curious into reading the work of Leibnitz and Newton regarding calculus, differentials, and integrals.
Do you think it could help me better understand those concepts?
If yes, can anyone help me to find those original works?
Maybe
I found people saying that it's useful, but no empirical evidence.
Example
In their paper Teaching and Learning Mathematics From Primary Historical Sources, Barnett et al. describe their method of introducing students to topics via historical texts.
Motivation
From the paper:
Usefulness
I could not, at first glance, find any empirical analysis of the effectiveness of this approach. They do get positive feedback from their students via a post-course questionnaire, though.
Access
I am not aware of any specific repository for historical mathematical texts, but I imagine they can be found like most historical texts (e.g. on archive).
See also