* [Scalable and Modular Architecture for CSS](https://smacss.com) - Jonathan Snook
* [Thinking in CSS](https://www.packtpub.com/packt/free-ebook/thinking-in-css) - Aravind Shenoy, Packt. (email address *requested*, not required)
* [Thinking in HTML](https://www.packtpub.com/packt/free-ebook/thinking-in-html) - Aravind Shenoy, Packt. (email address *requested*, not required)
* [Pro HTML5 Programming](https://web.archive.org/web/20181215200026/http://apress.jensimmons.com/v5/pro-html5-programming/ch0.html) - Jen Simmons, Chris O'Connor, Dylan Wooters, Peter Lubbers
* [Scalable and Modular Architecture for CSS](https://web.archive.org/web/20191116073929/http://smacss.com/) - Jonathan Snook
* [Understanding Flexbox: Everything you need to know](https://ohansemmanuel.github.io/uf_download.html) - Ohans Emmanuel
* [Web Audio API](http://chimera.labs.oreilly.com/books/1234000001552) - Boris Smus
* [Building Applications with Spring 5 and Vue.js 2](https://www.packtpub.com/free-ebooks/building-applications-spring-5-and-vuejs-2) - James J. Ye (Packt account *required*)
* [Software Architecture with Spring 5.0](https://www.packtpub.com/free-ebooks/software-architecture-spring-50) - René Enríquez, Alberto Salazar (Packt account *required*)
* [Spring Framework Reference Documentation](http://docs.spring.io/spring/docs/current/spring-framework-reference/html/) - Rod Johnson,Juergen Hoeller, Keith Donald,Colin Sampaleanu, Rob Harrop, Thomas Risberg, Alef Arendsen, Darren Davison, Dmitriy Kopylenko, Mark Pollack, Thierry Templier, Erwin Vervaet, Portia Tung, Ben Hale, Adrian Colyer, John Lewis, Costin Leau, Mark Fisher, Sam Brannen, Ramnivas Laddad, Arjen Poutsma, Chris Beams, Tareq Abedrabbo, Andy Clement, Dave Syer, Oliver Gierke, Rossen Stoyanchev, Phillip Webb, Rob Winch, Brian Clozel, Stephane Nicoll, Sebastien Deleuze ([PDF](https://docs.spring.io/spring/docs/current/spring-framework-reference/pdf/index.pdf))
* [Spring Framework Reference Documentation](https://docs.spring.io/spring/docs/current/spring-framework-reference/) - Rod Johnson et al.
#### Spring Boot
* [Spring Boot Reference Guide](http://docs.spring.io/spring-boot/docs/current/reference/html/) - Phillip Webb, Dave Syer, Josh Long, Stéphane Nicoll, Rob Winch, Andy Wilkinson, Marcel Overdijk, Christian Dupuis ([PDF](http://docs.spring.io/spring-boot/docs/current/reference/pdf/spring-boot-reference.pdf), [EPUB](http://docs.spring.io/spring-boot/docs/current/reference/epub/spring-boot-reference.epub))
* [Build applications in Python the antitextbook](http://github.com/thewhitetulip/build-app-with-python-antitextbook) (3.x) (HTML, PDF, EPUB, Mobi)
* [Building Skills in Object-Oriented Design (Python)](http://www.itmaybeahack.com/book/oodesign-python-2.1/latex/BuildingSkillsinOODesign.pdf) (PDF) (2.1.1)
* [Building Skills in Python](http://www.itmaybeahack.com/book/python-2.6/latex/BuildingSkillsinPython.pdf) (PDF) (2.6)
* [Code Like a Pythonista: Idiomatic Python](http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html)
* [Building Skills in Object-Oriented Design (Python)](https://web.archive.org/web/20190914230227/http://www.itmaybeahack.com/book/oodesign-python-2.1/latex/BuildingSkillsinOODesign.pdf) - Steven F. Lott (PDF) (2.1.1)
* [Building Skills in Python](https://web.archive.org/web/20190918094202/http://www.itmaybeahack.com/book/python-2.6/latex/BuildingSkillsinPython.pdf) - Steven F. Lott (PDF) (2.6)
* [Code Like a Pythonista: Idiomatic Python](https://web.archive.org/web/20180411011411/http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html) - David Goodger
* [Data Structures and Algorithms in Python](https://web.archive.org/web/20161016153130/http://www.brpreiss.com/books/opus7/html/book.html) - B. R. Preiss (PDF)
* [Functional Programming in Python](http://www.oreilly.com/programming/free/functional-programming-python.csp) (email address *requested*, not required)
* [Fundamentals of Python Programming](http://python.cs.southern.edu/pythonbook/pythonbook.pdf) - Richard L. Halterman (PDF) (3.2)
* [Fundamentals of Python Programming](https://web.archive.org/web/20191005170430/http://python.cs.southern.edu/pythonbook/pythonbook.pdf) - Richard L. Halterman (PDF) (:construction: *in process*)