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From a suggestion by @Alaharon123 here:
ossu#1078 (comment)

Author: waciumawanjohi

README.md

@@ -50,7 +50,7 @@ they belong in [extras/courses](extras/courses.md) or [extras/readings](extras/r
 - *Advanced CS*: corresponds roughly to the final year of a computer science curriculum, taking electives according to the student's interests
 - *Final Project*: a project for students to validate, consolidate, and display their knowledge, to be evaluated by their peers worldwide
 
-**Duration**. It is possible to finish within about 2 years if you plan carefully and devote roughly 20 hours/week to your studies. Learners can use [this spread
+**Duration**. It is possible to finish within about 2 years if you plan carefully and devote roughly 20 hours/week to your studies. Learners can use [this spreadsheet
 ](https://docs.google.com/spreadsheets/d/1bkUU90y4rKYQHwY5AR2iX6iiPTrPEsYs75GkCAkrgm4/copy) to estimate their end date. Make a copy and input your start date and expected hours per week in the `Timeline` sheet. As you work through courses you can enter your actual course completion dates in the `Curriculum Data` sheet and get updated completion estimates.
 
 **Cost**. All or nearly all course material is available for free. However, some courses may charge money for assignments/tests/projects to be graded.
@@ -228,7 +228,7 @@ Courses | Duration | Effort | Additional Text / Assignments| Prerequisites | Dis
 :-- | :--: | :--: | :--: | :--: | :--:
 [Build a Modern Computer from First Principles: From Nand to Tetris](https://www.coursera.org/learn/build-a-computer) ([alt](https://www.nand2tetris.org/)) | 6 weeks | 7-13 hours/week | - | C-like programming language | [chat](https://discord.gg/vxB2DRV)
 [Build a Modern Computer from First Principles: Nand to Tetris Part II ](https://www.coursera.org/learn/nand2tetris2) | 6 weeks | 12-18 hours/week | - | one of [these programming languages](https://user-images.githubusercontent.com/2046800/35426340-f6ce6358-026a-11e8-8bbb-4e95ac36b1d7.png), From Nand to Tetris Part I | [chat](https://discord.gg/AsUXcPu)
-[Operating Systems: Three Easy Pieces](coursepages/ostep/README.md) | 10-12 weeks | 6-10 hours/week | - | strong C programming | [chat](https://discord.gg/wZNgpep)
+[Operating Systems: Three Easy Pieces](coursepages/ostep/README.md) | 10-12 weeks | 6-10 hours/week | - | [strong C programming](/coursepages/ostep/README.md#prerequisites) | [chat](https://discord.gg/wZNgpep)
 [Computer Networking: a Top-Down Approach](http://gaia.cs.umass.edu/kurose_ross/online_lectures.htm)| 8 weeks | 4–12 hours/week | [Wireshark Labs](http://gaia.cs.umass.edu/kurose_ross/wireshark.php) | algebra, probability, basic CS | [chat](https://discord.gg/MJ9YXyV)
 
 ### Core theory

coursepages/ostep/README.md

@@ -15,7 +15,7 @@ In order to satisfy OSSU's curricular guidelines, you should either watch all th
 
 ## Prerequisites
 
-This class requires a lot of experience programming in C. You should finish one of the C books listed in the ***resources below*** *before* starting this course; if you try to learn C at the same time as the course material, you're likely to feel overwhelmed. If you haven't used C before, you should expect to spend a lot of time on this; it's hard to predict how long it might take for each person, but a rough estimate might be 8-10 hours per week for 3-5 weeks. You can always learn C alongside another OSSU course or even redo the exercises for other courses in C to gain practice with it.
+This class requires a lot of experience programming in C. You should finish one of the C books listed in the [resources below](#c) *before* starting this course; if you try to learn C at the same time as the course material, you're likely to feel overwhelmed. If you haven't used C before, you should expect to spend a lot of time on this; it's hard to predict how long it might take for each person, but a rough estimate might be 8-10 hours per week for 3-5 weeks. You can always learn C alongside another OSSU course or even redo the exercises for other courses in C to gain practice with it.
 
 You should also finish both parts of Nand2Tetris before starting this course. OSTEP focuses on the real-world x86 and x86_64 architectures, so you'll have to fill in some gaps in order to translate the concepts you learned in Nand2Tetris to a new architecture. You can do that with the x86 resources below, but note that they all assume you know C, so learn that first. This should take around 6-8 hours in total.