Books and sources concerning the mathematics of Leibniz and the feud with Newton I am trying to find books and other sources concerning the mathematical history of Leibniz, including the controversy due to the independent discoveries of calculus by both Newton and Leibniz. I can't seem to find many books that cover the controversy and the mathematics of Leibniz. The only books I found are The Calculus Wars: Newton, Leibniz, and the Greatest Mathematical Clash of All Time and The Early Mathematical Manuscripts of Leibniz. The first has strangely mixed reviews (though I hardly ever pay attention to reviews) and I am not so much interested in biographies of the two, but rather the controversy they shared. I am also interested in learning about Leibniz's mathematical contributions, but I get a lot of philosophy instead. The second is the most interesting one I have found; I honestly don't care about what Leibniz had to say about anything philosophy or religion, my concern is purely in regard to his impact on mathematics. 
I honestly thought about going to Germany, since Berlin is only about 600 km away from me. Leipzig is about 750 km away. I love traveling! But I really don't know how that would help me with sources and learning more about the debate and his history.
I only speak English and very little Polish, so sadly German and Latin sources aren't an option for me.
I found a similar question, but I am not so much interested in primary sources as I am interested in a condensed explanation of the issues and the accomplishments of Leibniz (these can, of course, be seperate texts). 
And thank you for your help and interest in this topic! 
 A: I put this question to an academic librarian
(or rather, I asked my wife, who is an academic librarian,
whether this would be a good question for you to put to an academic librarian;
but apparently that amounted to putting your question to her directly).
I obtained a couple of references which may (or may not) help.
One source is The claim of Leibnitz to the invention of the differential calculus. Translated from the German with considerable alterations and new addenda by the author, published in 1860 and in the public domain, available freely in full text at http://catalog.hathitrust.org/Record/000165115.
(And yes, the title spells Leibnitz with a t.)
At a glance, skimming over the text, it looks like slim pickings: bits of mathematics from people who were not Leibniz, primary sources quoted in Latin or French with only contextual information to guess what they mean, and so forth.
Also, while I have not seen the original German text, I got the impression that
the "considerable alterations" included the reassertion of Newton's priority.
(It was published in Cambridge, England, after all.)
But it may be interesting nevertheless.
A much more recent source is The Tangled Origins of the Leibnizian Calculus:
A Case Study of a Mathematical Revolution (2012), which I did not look over
(because it is not freely available online)
but whose publisher's blurb suggests that it goes into Leibniz's
actual mathematical writing at a level of detail and mathematical sophistication that would be suitable to your needs.
There is apparently a copy at the University of Bialystock that might
be available by interlibrary loan, depending on your relationship with
a cooperating university at this time. (You mentioned being within
600 km of Berlin.)
In any case, as your profile indicates you are currently a mathematics major,
you should be able to find a librarian at your university
with a subject specialty in mathematics or history of mathematics
who can help you get access to this book or to other suitable books and articles.
