diff --git a/README.md b/README.md
index ba95f41..90fa8ca 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ Courses | School | Duration | Effort | Frequency | Prerequisites
 :-- | :--: | :--: | :--: | :--: | :--:
 [Programming for Everybody (Getting Started with Python)](https://imp.i384100.net/GjkPZr)| University of Michigan | 4 weeks | 4-6 hours/week | self-paced | none
 [Python Data Structures](https://imp.i384100.net/python-ds)| University of Michigan | 4 weeks | 4-6 hours/week | self-paced | Programming for Everybody (Getting Started with Python)
-[Using Python to Access Web Data](https://click.linksynergy.com/deeplink?id=PtFMiHYfEVk&mid=40328&murl=https%3A%2F%2Fwww.coursera.org%2Flearn%2Fpython-network-data)| University of Michigan | 4 weeks | 4-6 hours/week | self-paced | Python Data Structures
+[Using Python to Access Web Data](https://imp.i384100.net/2rebdg)| University of Michigan | 4 weeks | 4-6 hours/week | self-paced | Python Data Structures
 [Using Databases with Python](https://imp.i384100.net/2rebdg)| University of Michigan | 3 weeks | 4-8 hours/week | self-paced | Using Python to Access Web Data
 [Capstone: Retrieving, Processing, and Visualizing Data with Python](https://imp.i384100.net/python-capstone) | University of Michigan | 2 weeks | 4-6 hours/week | self-paced | Using Databases with Python
 
@@ -27,12 +27,13 @@ Courses | School | Duration | Effort | Frequency | Prerequisites
 
 Courses | School | Duration | Effort | Frequency | Prerequisites
 :-- | :--: | :--: | :--: | :--: | :--:
-[Calculus 1A: Differentiation](https://www.edx.org/course/calculus-1a-differentiation) | MIT | 12 weeks | 6-10 hours/week | self-paced | [pre-calculus](https://www.edx.org/course/precalculus-asux-mat170x)
-[Calculus 1B: Integration](https://www.edx.org/course/calculus-1b-integration) | MIT | 15 weeks | 6-10 hours/week | self-paced | Calculus 1A: Differentiation
-[Calculus 1C: Coordinate Systems & Infinite Series](https://www.edx.org/course/calculus-1c-coordinate-systems-infinite-mitx-18-01-3x-0)| MIT | 8 weeks | 6-10 hours/week | self-paced | Calculus 1B: Integration
+[Calculus 1A: Differentiation](https://mitxonline.mit.edu/courses/course-v1:MITxT+18.01.1x/) | MIT | 12 weeks | 6-10 hours/week | self-paced | [pre-calculus](https://www.edx.org/course/precalculus-asux-mat170x)
+[Calculus 1B: Integration](https://mitxonline.mit.edu/courses/course-v1:MITxT+18.01.2x/) | MIT | 15 weeks | 6-10 hours/week | self-paced | Calculus 1A: Differentiation
+[Calculus 1C: Coordinate Systems & Infinite Series](https://mitxonline.mit.edu/courses/course-v1:MITxT+18.01.3x/)| MIT | 8 weeks | 6-10 hours/week | self-paced | Calculus 1B: Integration
 [Linear Algebra - Foundations to Frontiers](https://www.edx.org/course/linear-algebra-foundations-to-frontiers) | UT Austin | 15 weeks | 6-10 hours/week | self-paced | [pre-calculus](https://www.edx.org/course/precalculus-asux-mat170x)
 [Introduction to Probability and Data](https://imp.i384100.net/9WZ4E0) | Duke | 5 weeks | 5-7 hours/week | twice a month | none
-[Intro to Statistics ](https://imp.i115008.net/intro-to-statistics) | Udacity | 8 weeks | 5-7 hours/week | self-paced | none
+[Intro to Statistics ](https://click.linksynergy.com/deeplink?id=PtFMiHYfEVk&mid=53187&murl=https%3A%2F%2Fwww.udacity.com%2Fcourse%2Fintro-to-statistics--st101) | Udacity | 8 weeks | 5-7 hours/week | self-paced | none
+
 
 ## Data Science
 
@@ -48,10 +49,9 @@ Courses | School | Duration | Effort | Frequency | Prerequisites
 
 Courses | School | Duration | Effort | Frequency | Prerequisites
 :-- | :--: | :--: | :--: | :--: | :--:
-[Build a Modern Computer from First Principles: From Nand to Tetris](imp.i384100.net/6b13dV) | Hebrew University of Jerusalem | 6 weeks | 5 hours/week | twice a month | basic programming knowledge
+[Build a Modern Computer from First Principles: From Nand to Tetris](https://imp.i384100.net/6b13dV) | Hebrew University of Jerusalem | 6 weeks | 5 hours/week | twice a month | basic programming knowledge
 [Build a Modern Computer from First Principles: From Nand to Tetris II](https://imp.i384100.net/dovNVq) | Hebrew University of Jerusalem | 6 weeks | 10-15 hours/week | once a month | Build a Modern Computer from First Principles: From Nand to Tetris
-[Introduction to Operating Systems](https://imp.i115008.net/introduction-to-operating-systems)| Georgia Tech | 8 weeks | 5-8 hours/week | self-paced | Build a Modern Computer from First Principles: From Nand to Tetris II
-
+<!-- [Introduction to Operating Systems](https://click.linksynergy.com/deeplink?id=PtFMiHYfEVk&mid=53187&murl=https%3A%2F%2Fwww.udacity.com%2Fcourse%2Foperating-systems--ud923)| Udacity | 8 weeks | 5-8 hours/week | self-paced | Build a Modern Computer from First Principles: From Nand to Tetris II -->
 
 ## Theory
 
@@ -73,5 +73,5 @@ Courses | School | Duration | Effort | Frequency | Prerequisites
 
 Courses | School | Duration | Effort | Frequency | Prerequisites
 :-- | :--: | :--: | :--: | :--: | :--:
-[Linux Command Line Basics](https://imp.i115008.net/linux-command-line-basics) | Udacity | 1 week | 5 hours/week | self-paced | none
+[Linux Command Line Basics](https://imp.i384100.net/linux-cmd) | IBM | 1 week | 12 hours/week | self-paced | none
 [The Unix Workbench](https://imp.i384100.net/QOXZ4P) | JHU | 4 weeks | 4 hours/week | once a month | none