fix broken links (#2559)

free-courses-en.md

@@ -181,7 +181,7 @@
 * [Central Connecticut State University, Introduction to CS Using Java](http://chortle.ccsu.edu/CS151/cs151java.html)
 * [Introduction to Java](http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-092-introduction-to-programming-in-java-january-iap-2010/)
 * [Java for Complete Beginners](http://courses.caveofprogramming.com/courses/java-for-complete-beginners)
-* [Learn how to program: Java](https://www.learnhowtoprogram.com/java) - Epicodus Inc.
+* [Learn how to program: Java](https://www.learnhowtoprogram.com/java-june-2017) - Epicodus Inc.
 * [Princeton Algorithms, Part 1](https://www.coursera.org/course/algs4partI)
 * [Princeton Algorithms, Part 2](https://www.coursera.org/course/algs4partII)
 * [Problem Solving With Java](https://www.udacity.com/course/intro-to-java-programming--cs046)

free-podcasts-screencasts-en.md

@@ -143,7 +143,6 @@
 * [Podcast] - [Coding Blocks](http://www.codingblocks.net)
 * [Podcast] - [CTRL+CLICK CAST](http://ctrlclickcast.com)
 * [Podcast] - [Descriptive](http://descriptive.audio)
-* [Podcast] - [Dev Discussions](http://www.devdiscussions.com)
 * [Podcast] - [Developer On Fire](http://developeronfire.com)
 * [Podcast] - [Developer Tea](https://developertea.com)
 * [Podcast] - [DevelopersHangout](http://www.developershangout.io)
@@ -187,7 +186,6 @@
 
 ### Node.js
 
-* [Podcast] - [Node.js Screencast Series - Tutsowl](http://www.tutsowl.com)
 * [Podcast] - [Nodeup](http://nodeup.com)
 
 
@@ -228,7 +226,6 @@
 ### React JS
 
 * [Podcast] - [React Native Podcast](https://devchat.tv/react-native-radio)
-* [Podcast] - [React Podcast](http://reactpodcast.com)
 * [Screencast] - [ReactCasts](https://www.youtube.com/c/reactcasts)
 
 

free-podcasts-screencasts-ru.md

@@ -54,15 +54,9 @@
 
 * [Podcast] - [RWPod Podcast](http://rwpod.com)
 * [Podcast] - [RubyNoName Podcast](http://rubynoname.ru)
-* [Screencast] - [Ruby](http://ruby.hasbrains.org) - hasBrains
 * [Screencast] - [RubySchool (Ruby, Rails)](http://rubyschool.us) - Роман Пушкин
 
 
-#### Rails
-
-* [Screencast] - [Rails](http://rails.hasbrains.org) - hasBrains
-
-
 ### Webpack
 
 * [Screencast] - [Скринкаст Webpack](https://learn.javascript.ru/screencast/webpack) - Илья Кантор

free-programming-books-ar.md

@@ -21,11 +21,6 @@
 * [كتاب احترف الأردوينو](http://www.ev-center.com/uploads/2/1/2/6/21261678/arduino.pdf) (PDF)
 
 
-### Git
-
-* [GIT](http://blog.algorithmers.com/git/)
-
-
 ### Introduction to programming in Arabic
 
 * [مختصر دليل لغات البرمجة ](https://alyassen.github.io/Brief-guide-to-programming-languages-v1.2.4.pdf) (PDF)

free-programming-books-es.md

@@ -71,7 +71,6 @@
 * [Apuntes de Base de Datos 1, Universidad de Alicante](http://rua.ua.es/dspace/bitstream/10045/2990/1/ApuntesBD1.pdf) (PDF)
 * [Base de Datos](http://www.uoc.edu/masters/oficiales/img/913.pdf) - Mercedes Marqués (PDF)
 * [Base de Datos Avanzadas](http://repositori.uji.es/xmlui/bitstream/handle/10234/48034/s73.pdf) - Aramburu & Sanz Blasco (PDF)
-* [El modelo relacional y el álgebra relacional](http://www.colegiodrriodelaloza.edu.mx/informatica/Analisis%20Diseno%20e%20Implementacion%20de%20Algoritmos/17470106-BASES-de-DATOS-3-El-Modelo-Relacional-y-Algebra-Relacional.pdf) (PDF)
 * [Introducción a las Bases de Datos](http://ocw.uoc.edu/computer-science-technology-and-multimedia/bases-de-datos/bases-de-datos/P06_M2109_02147.pdf) (PDF)
 
 

free-programming-books-hu.md

@@ -102,7 +102,7 @@
 
 * [Bevezetés a Pythonba példákkal](http://mek.oszk.hu/08400/08436/index.phtml) - Raphaël Marvie, ford.: Daróczy Péter (PDF)
 * [Bevezetés a wxPythonba](http://mek.oszk.hu/08400/08446/index.phtml) - Jeremy Berthet, Gilles Doge, ford.: Daróczy Péter (PDF)
-* [Python-programozás](http://blog.molnardenes.hu/python-programozas-1-alapfogalmak/) - Molnár Dénes (HTML)
+* [Python-programozás](http://molnardenes.hu/blog/python-programozas-1-alapfogalmak.html) - Molnár Dénes (HTML)
 * [Tanuljunk meg programozni Python nyelven](http://mek.oszk.hu/08400/08435/index.phtml) - Gérard Swinnen, ford.: Daróczy Péter (PDF, ODT)
 
 

free-programming-books-id.md

@@ -11,7 +11,6 @@
 
 ### Android
 
-* [Tutorial Membuat Aplikasi Android **Special Edition**](http://www.slideshare.net/creatorb/tutorial-lengkap-cara-membuat-aplikasi-android-sederhana)
 * [Tutorial Membuat Aplikasi Galeri Foto Android](https://www.smashwords.com/books/view/533096)
 
 
@@ -51,7 +50,6 @@
 
 * [Pemrograman Web dengan PHP dan MySQL](http://achmatim.net/2009/04/15/buku-gratis-pemrograman-web-dengan-php-dan-mysql/)
 * [Tutorial Ebook PHP](http://www.ilmuwebsite.com/ebook-php-free-download)
-* [Tutorial PHP](http://www.codingku.com/php/)
 
 
 ### Python

free-programming-books-it.md

@@ -53,7 +53,6 @@
 
 ### C
 
-* [Guida al C di Blacklight](http://blacklight.gotdns.org/guidac.pdf) (PDF)
 * [Tricky C](http://www.dmi.unict.it/diraimondo/web/wp-content/uploads/classes/so/mirror-stuff/Tricky_C.pdf) (PDF)
 
 

free-programming-books-pl.md

@@ -32,7 +32,6 @@
 * [Programowanie webowe E14](https://www.youtube.com/playlist?list=PLOYHgt8dIdoxOp0wtNk9Sle5WUsBZc6kq)
 * [SVN](https://pl.wikibooks.org/wiki/Subversion)
 * [System kontroli wersji Subversion](http://www.gajdaw.pl/varia/subversion-system-kontroli-wersji-tutorial/)
-* [W obronie wolności](http://stallman.helion.pl)
 
 
 ### Android

free-programming-books-pt_BR.md

@@ -61,7 +61,6 @@
 
 ### Git
 
-* [Aprendendo Git](http://www.slideshare.net/bismarckjunior/aprendendo-git)
 * [Git - guia prático](http://rogerdudler.github.io/git-guide/index.pt_BR.html)
 * [Git Magic](http://www-cs-students.stanford.edu/~blynn/gitmagic/intl/pt_br/)
 * [Minicurso - Controle de Versão usando o Git](https://github.com/ltiaunesp/Git-Minicurso) - LTIA UNESP

free-programming-books.md

@@ -236,7 +236,6 @@
 * [DirectX manual](http://user.xmission.com/~legalize/book/download/index.html) (draft)
 * [GPU Gems](https://developer.nvidia.com/gpugems/GPUGems/gpugems_pref01.html)
 * [Graphics Programming Black Book](http://www.gamedev.net/page/resources/_/technical/graphics-programming-and-theory/graphics-programming-black-book-r1698)
-* [Grokking the GIMP](http://gimp-savvy.com/BOOK/index.html)
 * [Introduction to Modern OpenGL](https://open.gl)
 * [Learn OpenGL](http://learnopengl.com) - Joey de Vries
 * [Learning Modern 3D Graphics Programming](https://web.archive.org/web/20150225192611/http://www.arcsynthesis.org/gltut/index.html) (draft)
@@ -394,8 +393,8 @@
 * [Machine Learning, Neural and Statistical Classification](http://www1.maths.leeds.ac.uk/~charles/statlog/)
 * [Neural Networks and Deep Learning](http://neuralnetworksanddeeplearning.com)
 * [Probabilistic Models in the Study of Language](http://idiom.ucsd.edu/~rlevy/pmsl_textbook/text.html) (Draft, with R code)
-* [Reinforcement Learning: An Introduction](http://webdocs.cs.ualberta.ca/~sutton/book/ebook/the-book.html)
+* [Reinforcement Learning: An Introduction](http://incompleteideas.net/sutton/book/the-book.html)
-* [The Elements of Statistical Learning](http://www-stat.stanford.edu/~tibs/ElemStatLearn/) - Trevor Hastie, Robert Tibshirani, and Jerome Friedman
+* [The Elements of Statistical Learning](https://web.stanford.edu/~hastie/ElemStatLearn/) - Trevor Hastie, Robert Tibshirani, and Jerome Friedman
 * [The LION Way: Machine Learning plus Intelligent Optimization](http://www.e-booksdirectory.com/details.php?ebook=9575)
 * [The Python Game Book](http://thepythongamebook.com/en%3Astart)
 
@@ -433,7 +432,6 @@
 * [Linear Algebra: An Introduction to Mathematical Discourse](https://en.wikibooks.org/wiki/Linear_Algebra) - Jim Hefferon
 * [Mathematical Logic - an Introduction](http://www.ii.uib.no/~michal/und/i227/book/book.pdf) (PDF)
 * [Mathematics, MTH101A](http://home.iitk.ac.in/~psraj/mth101/) - P. Shunmugaraj, IIT Kanpur
-* [Notes on Differential Equations](http://www.math.cornell.edu/~bterrell/dn.pdf) - Robert E. Terrell (PDF)
 * [Number Theory](https://github.com/holdenlee/number-theory) - Holden Lee MIT
 * [OpenIntro Statistics](https://www.openintro.org/stat/textbook.php)
 * [Ordinary Differential Equations](https://en.wikibooks.org/wiki/Ordinary_Differential_Equations)
@@ -456,7 +454,7 @@
 * [2016 Software Development Salary Survey](http://www.oreilly.com/programming/free/2016-software-development-salary-survey-report.csp) *(Just fill the fields with any values)*
 * [97 Things Every Programmer Should Know - Extended](https://leanpub.com/97-Things-Every-Programmer-Should-Know-Extended)
 * [A Mathematical Theory of Communication](https://archive.org/details/bstj27-4-623) - Claude E.Shannon
-* [Ansible Up & Running (first three chapters)](https://www.ansible.com/blog/free-ansible-book) *(account required)*
+* [Ansible Up & Running (first three chapters)](https://www.ansible.com/ebooks) *(account required)*
 * [Asterisk™: The Definitive Guide](http://solmu.org/pub/help/Asterisk/3nd_Edition_for_Asterisk_1.8)
 * [Barcode Overview](http://www.tec-it.com/download/PDF/Barcode_Reference_EN.pdf) (PDF)
 * [Bitcoin and Cryptocurrency Technologies](https://d28rh4a8wq0iu5.cloudfront.net/bitcointech/readings/princeton_bitcoin_book.pdf) -  Arvind Narayanan, Joseph Bonneau, Edward Felten, Andrew Miller, Steven Goldfeder (PDF)
@@ -487,7 +485,6 @@
 * [How Computers Work](http://www.fastchip.net/howcomputerswork/p1.html) - R. Young
 * [How to Become a Programmer](http://softwarebyrob.wpengine.netdna-cdn.com/assets/Software_by_Rob%20_How_to_Become_a%20_Programmer_1.0.pdf) (PDF)
 * [How to Think Like a Computer Scientist](http://openbookproject.net/thinkcs/) - Peter Wentworth, Jeffrey Elkner, Allen B. Downey, and Chris Meyers
-* [I Am A Bug](http://www.amibug.com/iamabug/p01.html)
 * [Image Processing in C: Analyzing and Enhancing Digital Images](http://homepages.inf.ed.ac.uk/rbf/BOOKS/PHILLIPS/) - Dwayne Phillips
 * [Information Technology and the Networked Economy](http://florida.theorangegrove.org/og/file/49843a6a-9a9d-4bad-b4d4-d053f9cdf73e/1/InfoTechNetworkedEconomy.pdf) (PDF)
 * [IRPF90 Fortran code generator](https://www.gitbook.com/book/scemama/irpf90/details) - Anthony Scemama
@@ -790,7 +787,6 @@
 * [Programming from the Ground Up](http://mirror.unicorncloud.org/savannah-nongnu//pgubook/ProgrammingGroundUp-1-0-booksize.pdf) (PDF)
 * [Ralf Brown's Interrupt List](http://www.ctyme.com/rbrown.htm)
 * [Software optimization resources](http://www.agner.org/optimize/) A. Fog
-* [The Art of Assembly Language Programming](https://courses.engr.illinois.edu/ece390/books/artofasm/artofasm.html)
 * [Wizard Code](http://vendu.twodots.nl/wizardcode.html)
 * [x86 Assembly](https://en.wikibooks.org/wiki/X86_Assembly)
 
@@ -883,7 +879,6 @@
 
 ### C Sharp
 
-* [Beginners Guide to C# and the.NET Micro Framework](http://www.ghielectronics.com/downloads/FEZ/Beginners%20guide%20to%20NETMF.pdf) (PDF)
 * [C# Essentials](http://www.techotopia.com/index.php/C_Sharp_Essentials)
 * [C# Programming - Wikibook](https://en.wikibooks.org/wiki/C_Sharp_Programming)
 * [C# Yellow Book](http://www.csharpcourse.com) (intro to programming)
@@ -2174,11 +2169,6 @@ For resources on Angular, Backbone, D3, Dojo, Ember, Express, jQuery, Knockout,
 * [Stef's Free Online Smalltalk Books](http://stephane.ducasse.free.fr/FreeBooks.html) (meta-list)
 
 
-### Solidity
-
-* [A 101 Noob Intro to Programming Smart Contracts on Ethereum](https://consensys.github.io/developers/articles/101-noob-intro/) - Eva Shon
-
-
 ### Spark
 
 * [Databricks Spark Knowledge Base](https://www.gitbook.com/book/databricks/databricks-spark-knowledge-base/details)

free-programming-playgrounds.md

@@ -69,7 +69,6 @@
 ### NodeJS
 
 * [Ideone](http://ideone.com)
-* [Runnable](http://code.runnable.com)
 
 
 ### Perl
@@ -93,7 +92,6 @@
 ### Ruby
 
 * [Codepad](http://codepad.org)
-* [Runnable](http://code.runnable.com)
 
 
 ### Rust

javascript-frameworks-resources-pt_BR.md

@@ -2,7 +2,7 @@
 
 * [Adicionar Bootstrap e Font-awesome no projeto criado com o Vue Cli](http://www.vedovelli.com.br/frontend/adicionar-bootstrap-e-font-awesome-no-projeto-criado-com-o-vue-cli/)
 * [Documentação pt-BR](https://br.vuejs.org/v2/guide/)
-* [Série de vídeos sobre Vue.js](https://vimeo.com/channels/1115590/videos/) - [Origem: Vedcasts](http://www.vedcasts.com.br/hibernando)
+* [Série de vídeos sobre Vue.js](https://vimeo.com/channels/1115590/videos/) - [Origem: Vedovelli](http://www.vedovelli.com.br/screencasts/)
 * [Vue.js Brasil - Artigos em Português sobre Vue.js](http://www.vuejs-brasil.com.br)
 * [VueJS: Filtro para criar URL’s amigáveis](http://web.archive.org/web/20160331162636/http://carlosgartner.com.br/vuejs-filtro-para-criar-urls-amigaveis/)
 

javascript-frameworks-resources.md

@@ -116,7 +116,7 @@
 * [React Enlightenment](https://www.gitbook.com/book/frontendmasters/react-enlightenment/details)
 * [React In-depth: An exploration of UI development](https://www.gitbook.com/book/developmentarc/react-indepth/details)
 * [React Primer Draft](https://github.com/mikechau/react-primer-draft)
-* [React Tutorial](https://facebook.github.io/react/docs/tutorial.html)
+* [React Tutorial](https://reactjs.org/tutorial/tutorial.html)
 * React Tutorial by Josh Finnie
   * [Part 1](http://www.joshfinnie.com/blog/reactjs-tutorial-part-1/)
   * [Part 2](http://www.joshfinnie.com/blog/reactjs-tutorial-part-2/)

problem-sets-competitive-programming.md

@@ -25,7 +25,6 @@
 * [Just another Golf Coding](http://jagc.org)
 * [Kattis](https://open.kattis.com)
 * [Microcorruption](https://microcorruption.com/login)
-* [Saratov State University](http://acm.sgu.ru/index.php)
 * [Sphere Online Judge](http://www.spoj.com/contests)
 * [Topcoder](https://www.topcoder.com)