References

The are dozens of incredible references online dealing with the history of computing, and especially about the TI-99/4 and TI-99/4A computers. I list as many as I can find for your reference:

• 99er - The TI-99/4A Home Computer Page = One of my favorite TI-99/4A websites. This site provides a ton of information about the computer and includes downloads of many TI-99/4A manuals (although most, I've found, are of lower quality).
• AtariAge TI-99/4A Forum = A great TI-99/4A forum covering many topics and offering multiple downloads.
• Centre for Computing History = This is a UK-based, general computing history website that has numerous articles involving the TI-99/4A.
• Eli's Software Encyclopedia = This software focused website includes many articles about TI-99/4A software. It's written using MediaWiki (the same software as this website and Wikipedia).
• GameFAQs = A large database of gaming information for many consoles, not just the TI.
• Games Database = A large, generalized database for all types of video games, including many TI-99/4A games.
• GameSpot = Another database containing information about many games from numerous gaming systems.
• The Giant List of Classic Games Programmers = Exactly what it sounds like, this site focuses on programmers, and the games and systems they worked on, specifically on systems pre-NES.
• Internet Archive: Texas Instrument TI 99/4A Books Collection = This is a collection of scanned manuals, magazine, and other TI-99/4A references about the TI-99/4A. Not easily searchable, but fun to puruse. While you're visiting the Internet Archive, search it for other TI-99/4A texts that haven't made it into the TI-99/4A Collection.
• Mainbyte = A retrogaming website including information about the TS 1000, TI-99/4A, TRS 80 PC-4, and the VIC-20.
• Moby Games = A general video game website that hosts several TI-99/4A game pages.
• Ninerpedia = A great resource run on Mediawiki (the same software as Wikipedia and this website).
• Obsolete Technology Website = This website is dedicated to preserving the history, and important background information covering computing devices from 1970 through 1993.
• Pixelated Arcade = Refers to itself as "A museum of vintage video games featuring photos, information, screenshots, artwork, and more." It really contains what it says.
• Rediware's TI-99/4A Page = Rediware has information about software and other items, including a fairly extensive set of TI-99/4A pages. I link to Rediware's main TI-99/4As landing page.
• Retrogaming Times Monthly = An archive of an older website covering multiple 1980's computing devices.
• The TI-99/4A Tech Pages = A mostly hardware focused website.
• TI-99/4A Video Game House = A strictly TI-99/4A page covering many of the most popular video games for the TI-99/4A. One of my favorite resources. It hasn't been updated for a while, but neither has the TI-99/4A, so it's totally legit.
• Whtech = A large database of downloadable files dealing with the TI-99/4A. Although there is a ton of information, the website isn't terribly intuitive nor visually appealing. But, if you know what you're looking for, Whtech probably has it.
• WikiPedia = A site I'm sure everyone is familiar with. This presents many articles on TI-99/4A hardware and software.