diff --git a/README.md b/README.md
index 8915a90..705425d 100644
--- a/README.md
+++ b/README.md
@@ -921,7 +921,7 @@ Graphs can be used to represent many problems in computer science, so this secti
     - When it is appropriate to use it?
     - How is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamic Programming
     - You probably won't see any dynamic programming problems in your interview, but it's worth being able to recognize a problem as being a candidate for dynamic programming.
diff --git a/translations/README-ar.md b/translations/README-ar.md
index be6269f..31b5023 100644
--- a/translations/README-ar.md
+++ b/translations/README-ar.md
@@ -913,7 +913,7 @@ Graphs can be used to represent many problems in computer science, so this secti
     - When it is appropriate to use it?
     - How is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamic Programming
     - You probably won't see any dynamic programming problems in your interview, but it's worth being able to recognize a problem as being a candidate for dynamic programming.
diff --git a/translations/README-bn.md b/translations/README-bn.md
index 319931a..cdb19fe 100644
Binary files a/translations/README-bn.md and b/translations/README-bn.md differ
diff --git a/translations/README-cn.md b/translations/README-cn.md
index 2af8960..9cc2039 100644
--- a/translations/README-cn.md
+++ b/translations/README-cn.md
@@ -851,7 +851,7 @@
     - 什么时候适合使用
     - 尾递归会更好么?
         - [ ] [什么是尾递归以及为什么它如此糟糕?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [尾递归（视频）](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [尾递归（视频）](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### 动态规划（Dynamic Programming）
     - 在你的面试中或许没有任何动态规划的问题，但能够知道一个题目可以使用动态规划来解决是很重要的。
diff --git a/translations/README-de.md b/translations/README-de.md
index c6de9fd..1d57792 100644
--- a/translations/README-de.md
+++ b/translations/README-de.md
@@ -1002,7 +1002,7 @@ Graphen können genutzt werden, um damit viele verschiedene Probleme in der Info
     - wann sollte man es benutzen
     - Wann ist Endrekursion gut?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamische Programming
     - Wahrscheinlich wirst du im Vorstellungsgespräch nichts mit dynamischer Programmierung zu tun haben, aber es ist wert zu erkennen, wann ein Problem für dynamische Programmierung geeignet ist.
diff --git a/translations/README-es.md b/translations/README-es.md
index 9ac2926..c256a5a 100644
--- a/translations/README-es.md
+++ b/translations/README-es.md
@@ -935,7 +935,7 @@ Obtendrá más práctica de grafos en el libro de Skiena (vea Sección de libros
     - Cuando es apropiado usarlo
     - ¿Cómo es la recursión de cola mejor que no?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Programación Dinámica
     - Este tema puede ser bastante difícil, ya que cada problema soluble PD debe definirse como una relación de recursión, y llegar a ella puede ser complicado.
diff --git a/translations/README-fr.md b/translations/README-fr.md
index d4204c2..1d73ade 100644
--- a/translations/README-fr.md
+++ b/translations/README-fr.md
@@ -986,7 +986,7 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Object-Oriented Programming
     - [ ] [Optional: UML 2.0 Series (video)](https://www.youtube.com/watch?v=OkC7HKtiZC0&list=PLGLfVvz_LVvQ5G-LdJ8RLqe-ndo7QITYc)
diff --git a/translations/README-he.md b/translations/README-he.md
index 5e865fa..3a4fbaf 100644
--- a/translations/README-he.md
+++ b/translations/README-he.md
@@ -991,7 +991,7 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Object-Oriented Programming
     - [ ] [Optional: UML 2.0 Series (video)](https://www.youtube.com/watch?v=OkC7HKtiZC0&list=PLGLfVvz_LVvQ5G-LdJ8RLqe-ndo7QITYc)
diff --git a/translations/README-hi.md b/translations/README-hi.md
index 7120478..38457e1 100644
--- a/translations/README-hi.md
+++ b/translations/README-hi.md
@@ -936,7 +936,7 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (विडियो)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (विडियो)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
  
 - ### Dynamic Programming
     - This subject can be pretty difficult, as each DP soluble problem must be defined as a recursion relation, and coming up with it can be tricky.
diff --git a/translations/README-id.md b/translations/README-id.md
index 1669f21..4b551c1 100644
--- a/translations/README-id.md
+++ b/translations/README-id.md
@@ -857,7 +857,7 @@ Graf (Graphs) dapat digunakan untuk merepresentasikan banyak masalah dalam ilmu
     - Kapan saat yang tepat untuk menggunakannya?
     - Bagaimana rekursi ekor lebih baik daripada tidak?
         - [ ] [Apa Itu Rekursi Ekor Mengapa Sangat Buruk?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Rekursi Ekor (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Rekursi Ekor (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Pemrograman Dinamis
     - Anda mungkin tidak akan melihat masalah pemrograman dinamis dalam wawancara Anda, tetapi ada baiknya mengenali masalah sebagai kandidat untuk pemrograman dinamis (Dynamic Programming).
diff --git a/translations/README-ja.md b/translations/README-ja.md
index 893ceb7..49bb56c 100644
--- a/translations/README-ja.md
+++ b/translations/README-ja.md
@@ -846,7 +846,7 @@ Skienaの本(下記の書籍の節を参照)と面接の書籍
 	- それを使用するのが適切なとき
 	- 尾の再帰はどのように優れていないのですか？
 		- [ ]  [テール再帰とは何かなぜそれが悪いのですか？](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-		- [ ]  [テール再帰(ビデオ)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+		- [ ]  [テール再帰(ビデオ)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### 動的プログラミング
 	- この問題はかなり難しいかもしれません。なぜなら、それぞれのDP可溶性問題は再帰関係として定義されなければならず、それを思い付くのは難しいかもしれないからです。
diff --git a/translations/README-kh.md b/translations/README-kh.md
index 4b410b1..6d05777 100644
--- a/translations/README-kh.md
+++ b/translations/README-kh.md
@@ -938,7 +938,7 @@ Graphs អាចត្រូវបានប្រើដើម្បីបង្
     - នៅពេលដែលសមរម្យដើម្បីប្រើវា
     - តេី tail recursion ប្រសើរជាងអត់?
         - [ ] [អ្វីជា Tail Recursion និង ហេតុអ្វីបានជាវាអាក្រក់?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (វីដេអូ)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (វីដេអូ)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamic Programming
     - អ្នកប្រហែលជាមិនឃើញមានបញ្ហានៃការសរសេរកម្មវិធី dynamic programming នៅក្នុងបទសម្ភាសន៍របស់អ្នកទេ ប៉ុន្តែវាសមនឹងទទួលបានការទទួលស្គាល់នូវបញ្ហាមួយក្នុងនាមជាបេក្ខជនសម្រាប់ការសរសេរកម្មវិធី dynamic programming។
diff --git a/translations/README-ko.md b/translations/README-ko.md
index 80023e8..9249d56 100644
--- a/translations/README-ko.md
+++ b/translations/README-ko.md
@@ -920,7 +920,7 @@ Skiena의 책(아래의 책 섹션 참조)과 인터뷰 책에서 더 많은 그
     - 재귀는 언제 사용해야 하는 지
     - 꼬리 재귀를 사용하는 게 그렇지 않은 것보다 얼마나 나은가요?
         - [ ] [꼬리 재귀가 무엇이고 왜 그게 좋지 않은지에 대하여](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [꼬리 재귀 (영상)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [꼬리 재귀 (영상)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 
 - ### Dynamic Programming
diff --git a/translations/README-pl.md b/translations/README-pl.md
index 387ce0a..f467e5b 100644
--- a/translations/README-pl.md
+++ b/translations/README-pl.md
@@ -904,7 +904,7 @@ Grafy mogą być wykorzystane do przedstawienia wielu problemów w informatyce,
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (wideo)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (wideo)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Programowanie dynamiczne
     - Prawdopodobnie nie będziesz mieć programowania dynamicznego podczas swojej rekrutacji, ale warto umieć rozpoznawać problem, jako kandydata na ten właśnie rodzaj.
diff --git a/translations/README-ptbr.md b/translations/README-ptbr.md
index cf3b295..fc41d76 100644
--- a/translations/README-ptbr.md
+++ b/translations/README-ptbr.md
@@ -939,7 +939,7 @@ Você ganhará mais prática com grafos no livro do Skiena (veja a seção de li
     - quando é apropriado usá-la
     - como a recursão de cauda é melhor do que nada?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad) (O Que É Recursão de Cauda E Por Que Ela É Tão Ruim?)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc) (Recursão de Cauda - vídeo)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1) (Recursão de Cauda - vídeo)
 
 - ### Programação Dinâmica
     - Esse assunto pode ser bem difícil, já que cada problema solúvel de PD deve ser definido como uma relação de recursão, e isso pode ser complicado.
diff --git a/translations/README-ru.md b/translations/README-ru.md
index 00b4b07..b3ce937 100644
--- a/translations/README-ru.md
+++ b/translations/README-ru.md
@@ -995,7 +995,7 @@ Google не возьмёт тебя на работу.
     - когда уместно использование рекурсии?
     - когда лучше использовать хвостовую рекурсию?
         - [ ] [Что такое хвостовая рекурсия и почему её использование нежелательно?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Хвостовая рекурсия (видео)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Хвостовая рекурсия (видео)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Объектно-ориентированное программирование
     - [ ] [Дополнительно: Серия уроков по UML 2.0 (видео)](https://www.youtube.com/watch?v=OkC7HKtiZC0&list=PLGLfVvz_LVvQ5G-LdJ8RLqe-ndo7QITYc)
diff --git a/translations/README-th.md b/translations/README-th.md
index e7c69d7..c8b6683 100644
--- a/translations/README-th.md
+++ b/translations/README-th.md
@@ -916,7 +916,7 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamic Programming
     - This subject can be pretty difficult, as each DP soluble problem must be defined as a recursion relation, and coming up with it can be tricky.
diff --git a/translations/README-tr.md b/translations/README-tr.md
index 90715cd..efb9745 100644
--- a/translations/README-tr.md
+++ b/translations/README-tr.md
@@ -922,7 +922,7 @@ Graflar, bilgisayar bilimlerinde birçok sorunu temsil etmek için kullanılabil
     - Ne zaman kullanmak uygun olur?
     - Parçalı özyineleme olmamasından nasıl daha iyidir?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dinamik Programlama
     - Mülakatınızda muhtemelen herhangi bir dinamik programlama sorusu görmeyeceksiniz, ancak bir soruyu dinamik programlama adayı olarak tanımaya değer.
diff --git a/translations/README-tw.md b/translations/README-tw.md
index da39819..d8eb6ce 100644
--- a/translations/README-tw.md
+++ b/translations/README-tw.md
@@ -881,7 +881,7 @@
     - 什麼時候適合用這些
     - tail recursion沒有比較好?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (影片)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (影片)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### 動態規劃
     - 在你的面試中或許沒有任何動態規劃的問題，但能夠知道一個題目可以使用動態規劃來解決是很重要的。
diff --git a/translations/README-uk.md b/translations/README-uk.md
index 2f00062..7bfeb00 100644
--- a/translations/README-uk.md
+++ b/translations/README-uk.md
@@ -965,7 +965,7 @@ You'll get more graph practice in Skiena's book (see Books section below) and th
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamic Programming
     - This subject can be pretty difficult, as each DP soluble problem must be defined as a recursion relation, and coming up with it can be tricky.
diff --git a/translations/README-ur.md b/translations/README-ur.md
index 02566bf..17f4534 100644
--- a/translations/README-ur.md
+++ b/translations/README-ur.md
@@ -916,7 +916,7 @@ Graphs can be used to represent many problems in computer science, so this secti
     - when it is appropriate to use it
     - how is tail recursion better than not?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dynamic Programming
     - You probably won't see any dynamic programming problems in your interview, but it's worth being able to recognize a problem as being a candidate for dynamic programming.
diff --git a/translations/README-uz.md b/translations/README-uz.md
index d562754..3d671d0 100644
--- a/translations/README-uz.md
+++ b/translations/README-uz.md
@@ -891,7 +891,7 @@ Computer science da graflar bir talay masalalarni tasvirlashda ishlatiladi. Shun
     - Rekursiyani qachon ishlatish yaxshi?
     - Nega tail rekursiya (tail recursion) yaxshi narsa?
         - [ ] [What Is Tail Recursion Why Is It So Bad?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Tail Recursion (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Tail Recursion (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Dinamik dasturlash (Dynamic Programming)
     - Katta ehtimollik bilan sizni intervyuingizda dinamik dasturlash masalalari bo'lmaydi, lekin shunday masalani dinamik dasturlashga mosligini aniqlay olishni o'rganish arzigulik
diff --git a/translations/README-vi.md b/translations/README-vi.md
index 46a86f5..4d62426 100644
--- a/translations/README-vi.md
+++ b/translations/README-vi.md
@@ -961,7 +961,7 @@ Bạn sẽ biết thêm nhiều ứng dụng của đồ thị trong sách của
     - Khi nào thích hợp để sử dụng?
     - Đệ quy đuôi tốt hơn hay không như thế nào?
         - [ ] [Đệ quy đuôi là gì Tại sao nó không tốt(What Is Tail Recursion Why Is It So Bad)?](https://www.quora.com/What-is-tail-recursion-Why-is-it-so-bad)
-        - [ ] [Đệ quy đuôi (Tail Recursion) (video)](https://www.youtube.com/watch?v=L1jjXGfxozc)
+        - [ ] [Đệ quy đuôi (Tail Recursion) (video)](https://www.coursera.org/lecture/programming-languages/tail-recursion-YZic1)
 
 - ### Quy hoạch động
     - Chủ đề này có thể hơi khó, và các bài toán giải được bằng quy hoạch động (Dynamic Programming - DP) phải được định nghĩa ở dạng quan hệ hồi quy, và tìm ra giải pháp quy hoạch động cũng không đơn giản.