diff --git a/extras/courses.md b/extras/courses.md
index 1d0f356..b661c5e 100644
--- a/extras/courses.md
+++ b/extras/courses.md
@@ -39,21 +39,15 @@ 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
+[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
-[Analysis of Algorithms (Sedgewick)](https://www.coursera.org/course/aofa)| 6 weeks | 6-8 hours/week
 [Programming Challenges (Skiena)](http://www3.cs.stonybrook.edu/~skiena/392/) | 14 weeks | 6-8 hours/week
-[Mathematical Logic and Algorithms Theory](https://iversity.org/en/courses/mathematical-logic-and-algorithms-theory) | 7 weeks | 3-4 hours/week
-[Algorithmic Toolbox](https://www.coursera.org/learn/algorithmic-toolbox/) | 5 weeks | 4-8 hours/week
-[Algorithms on Graphs and Trees](https://www.coursera.org/learn/algorithms-on-graphs-and-trees/) | - | -
-[Algorithms on Strings](https://www.coursera.org/learn/algorithms-on-strings/) | - | -
-[Advanced Algorithms and Complexity](https://www.coursera.org/learn/advanced-algorithms-and-complexity/) | - | -
+[Data Structures and Algorithms (Specialization)](https://www.coursera.org/specializations/data-structures-algorithms) | 25 weeks | 3-10 hours/week
 [Algorithmic Thinking (Part 1)](https://www.coursera.org/learn/algorithmic-thinking-1/) | - | -
 [Algorithmic Thinking (Part 2)](https://www.coursera.org/learn/algorithmic-thinking-2/) | - | -
 [Statistical Mechanics: Algorithms and Computations](https://www.coursera.org/learn/statistical-mechanics/) | - | -
 [Approximation Algorithms Part I](https://www.coursera.org/learn/approximation-algorithms-part-1/) | - | -
 [Approximation Algorithms Part II](https://www.coursera.org/learn/approximation-algorithms-part-2/) | - | -
-[Algorithms: Design and Analysis, Part 1](https://www.coursera.org/course/algo) | 6 weeks | 5-7 hours/week
-[Algorithms: Design and Analysis, Part 2](https://www.coursera.org/course/algo2) | 6 weeks | 6-10 hours/week
 
 ## Applications