diff --git a/README.md b/README.md
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+++ b/README.md
@@ -208,9 +208,8 @@ Courses | Duration | Effort | Prerequisites | Discussion
 
 Courses | Duration | Effort | Additional Text / Assignments| Prerequisites | Discussion
 :-- | :--: | :--: | :--: | :--: | :--:
-[Build a Modern Computer from First Principles: From Nand to Tetris](https://www.coursera.org/learn/build-a-computer) ([alternative](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 | - | Nand to Tetris Part II | [chat](https://discord.gg/wZNgpep)
+[Build a Modern Computer from First Principles: From Nand to Tetris](https://www.nand2tetris.org/) | 12 weeks | 10-16 hours/week | - | C-like programming language | [chat](https://discord.gg/vxB2DRV)
+[Operating Systems: Three Easy Pieces](coursepages/ostep/README.md) | 10-12 weeks | 6-10 hours/week | - | Nand to Tetris | [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
@@ -346,7 +345,7 @@ Courses | Duration | Effort | Prerequisites
 
 Courses | Duration | Effort | Prerequisites | Notes
 :-- | :--: | :--: | :--: | :--:
-[Computation Structures 1: Digital Circuits](https://learning.edx.org/course/course-v1:MITx+6.004.1x_3+3T2016) [alternative 1](https://ocw.mit.edu/courses/6-004-computation-structures-spring-2017/) [alternative 2](https://ocw.mit.edu/courses/6-004-computation-structures-spring-2009/) | 10 weeks | 6 hours/week | [Nand2Tetris II](https://www.coursera.org/learn/nand2tetris2) | Alternate links contain all 3 courses.
+[Computation Structures 1: Digital Circuits](https://learning.edx.org/course/course-v1:MITx+6.004.1x_3+3T2016) [alternative 1](https://ocw.mit.edu/courses/6-004-computation-structures-spring-2017/) [alternative 2](https://ocw.mit.edu/courses/6-004-computation-structures-spring-2009/) | 10 weeks | 6 hours/week | [Nand2Tetris](https://www.nand2tetris.org/) | Alternate links contain all 3 courses.
 [Computation Structures 2: Computer Architecture](https://learning.edx.org/course/course-v1:MITx+6.004.2x+3T2015) | 10 weeks | 6 hours/week | Computation Structures 1 | - 
 [Computation Structures 3: Computer Organization](https://learning.edx.org/course/course-v1:MITx+6.004.3x_2+1T2017) | 10 weeks | 6 hours/week | Computation Structures 2 | -