Visual Programming Languages: A Survey
- This paper by Marat Boshernitsan includes an historical overview of some of the pioneering efforts in the field.
- http://nitsan.org/~maratb/cs263/

The Semicolon Wars
- History and critique of disagreements over language design details, citing some specific traits; by Brian Hayes. American Scientist.
- http://www.americanscientist.org/template/AssetDetail/assetid/51982/

O'Reilly: The History of Programming Languages
- A poster plots over 50 programming languages on a multi-layered, color-coded timeline.
- http://oreilly.com/news/languageposter_0504.html

History and Comparison of Programming Languages
- Papers on use history of: comments, labels, literals, parentheses.
- http://www.gavilan.edu/csis/languages/history.html

History and Evolution
- A list of computer languages and some links to compilers for these languages.
- http://www.scriptol.org/history.php

The History of Computer Programming Languages
- Short concise article on programming language history with some links.
- http://www.princeton.edu/~ferguson/adw/programming_languages.shtml

Wikipedia: PL/I
- An encyclopedia description of PL/I history with many links to programming terms.
- http://en.wikipedia.org/wiki/PL/I_programming_language

Historic Documents in Computer Science
- Original, historic first documents for many early programming languages, like language manualsa, scanned and converted to PDF form.
- http://www.fh-jena.de/~kleine/history/

Diagram of Languages
- Two diagrams showing how many languages are related to each other.
- http://merd.sourceforge.net/pixel/language-study/diagram.html

Computer Languages History
- Timeline chart, 1954 to today, printable; links to homes of many languages.
- http://www.levenez.com/lang/

A Brief History of Programming Languages
- A special Byte Magazine article published for Byte's 20th anniversary special report
- http://www.byte.com/art/9509/sec7/art19.htm