diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 11b7909..0951c49 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -9,4 +9,10 @@ the subreddit is recommended as there people may be able to give you suggested a
 3. If you have *specific* and *substantive* criticisms of the curriculum, i.e. problems related to the progression/content of courses it would be appropriate to [open an issue](https://help.github.com/articles/creating-an-issue/) and give us your suggestions.
 4. If you have *non-substantive* updates to make to the curriculum, such as a course's URL having been moved, spelling/syntax errors, etc., please send a [pull request](https://help.github.com/articles/using-pull-requests/) to fix any mistakes that you have found.
 5. If you want to customize the curriculum for yourself, do of course [fork this project](https://help.github.com/articles/fork-a-repo/).
-6. If you want to suggest a new resource, send a pull request adding such resource to the [extras](https://github.com/ossu/computer-science/tree/master/extras) section.
+6. If you want to suggest a new resource, send a pull request adding such resource to the [extras](https://github.com/open-source-society/computer-science/tree/master/extras) section.
+
+# Learning Git
+
+To be able to create high-quality pull requests, it is recommended that you learn how to use the Git version control system.
+One of the best primers on the subject is a free ebook called [Ry's Git Tutorial](https://www.amazon.com/dp/B00QFIA5OC/).
+If you prefer a course-style introduction, try [Introduction to Git and GitHub](https://www.udacity.com/course/how-to-use-git-and-github--ud775).
diff --git a/README.md b/README.md
index a9d68c8..0bf656e 100644
--- a/README.md
+++ b/README.md
@@ -321,7 +321,6 @@ Courses | Duration | Effort | Prerequisites
 ### Advanced math
 
 **Topics covered**:
-`real analysis`
 `parametric equations`
 `polar coordinate systems`
 `multivariable integrals`
@@ -331,7 +330,6 @@ Courses | Duration | Effort | Prerequisites
 
 Courses | Duration | Effort | Prerequisites
 :-- | :--: | :--: | :--:
-[Introduction to Mathematical Thinking](https://www.coursera.org/learn/mathematical-thinking) | 10 weeks | 10 hours/week | pre-calculus
 [Calculus: Parametric Equations and Polar Coordinates](https://ocw.mit.edu/courses/mathematics/18-01sc-single-variable-calculus-fall-2010/unit-4-techniques-of-integration/part-c-parametric-equations-and-polar-coordinates/) | - | - | single-variable calculus (Calculus Two)
 [Multivariable Calculus](https://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/index.htm) | 13 weeks | 12 hours/week | Parametric Equations and Polar Coordinates
 [Introduction to Probability - The Science of Uncertainty](https://www.edx.org/course/introduction-probability-science-mitx-6-041x-2) | 18 weeks | 12 hours/week | Multivariable Calculus
diff --git a/extras/courses.md b/extras/courses.md
index c97d805..18ee99e 100644
--- a/extras/courses.md
+++ b/extras/courses.md
@@ -23,7 +23,8 @@ Courses | Duration | Effort
 
 Courses | Duration | Effort
 :-- | :--: | :--:
-[Effective Thinking Through Mathematics](https://www.edx.org/course/effective-thinking-through-mathematics-utaustinx-ut-9-01x-0) | 4 weeks | 2 hours/week | none
+[Effective Thinking Through Mathematics](https://www.edx.org/course/effective-thinking-through-mathematics-utaustinx-ut-9-01x-0) | 4 weeks | 2 hours/week
+[Introduction to Mathematical Thinking](https://www.coursera.org/learn/mathematical-thinking) | 10 weeks | 10 hours/week
 [Introduction to Probability and Data](https://www.coursera.org/learn/probability-intro)| - | -
 [Linear Algebra (Strang)](https://ocw.mit.edu/courses/mathematics/18-06-linear-algebra-spring-2010/index.htm) | - | -
 
@@ -41,8 +42,8 @@ Courses | Duration | Effort
 
 Courses | Duration | Effort
 :-- | :--: | :--:
-[Algorithms, Part I](https://www.coursera.org/learn/algorithms-part1) | 6 weeks | 6-12 hours/week | some programming
-[Algorithms, Part II](https://www.coursera.org/learn/algorithms-part2) | 6 weeks | 6-12 hours/week | Algorithms, Part I
+[Algorithms, Part I](https://www.coursera.org/learn/algorithms-part1) | 6 weeks | 6-12 hours/week
+[Algorithms, Part II](https://www.coursera.org/learn/algorithms-part2) | 6 weeks | 6-12 hours/week
 [Analysis of Algorithms (Sedgewick)](https://www.coursera.org/learn/analysis-of-algorithms) | 6 weeks | 6-8 hours/week
 [Analysis of Algorithms (Skiena)](http://www3.cs.stonybrook.edu/~skiena/373/) | 15 weeks | 6-8 hours/week
 [Programming Challenges (Skiena)](http://www3.cs.stonybrook.edu/~skiena/392/) | 14 weeks | 6-8 hours/week
diff --git a/extras/readings.md b/extras/readings.md
index e9c870b..aed6f2e 100644
--- a/extras/readings.md
+++ b/extras/readings.md
@@ -51,6 +51,7 @@ Name | Author(s)
 [Introduction to Algorithms (3rd Edition)](http://www.amazon.com/Introduction-Algorithms-3rd-MIT-Press/dp/0262033844/) | Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein
 [The Algorithm Design Manual](https://www.amazon.com/gp/product/1848000693) | Steven Skiena
 [Category Theory: A Gentle Introduction](http://www.logicmatters.net/resources/pdfs/GentleIntro.pdf) | Peter Smith
+[Category Theory for Programmers: The Preface](https://bartoszmilewski.com/2014/10/28/category-theory-for-programmers-the-preface/) | Bartosz Milewski
 
 ## Applications