$TopDirectory
Since Version 5.0 (released in 2003), $TopDirectory has been superseded by $InstallationDirectory and $BaseDirectory.
Wolfram Research (1996), $TopDirectory, Wolfram Language function, https://reference.wolfram.com/language/ref/$TopDirectory.html (updated 2002).
Text
Wolfram Research (1996), $TopDirectory, Wolfram Language function, https://reference.wolfram.com/language/ref/$TopDirectory.html (updated 2002).
CMS
Wolfram Language. 1996. "$TopDirectory." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2002. https://reference.wolfram.com/language/ref/$TopDirectory.html.
APA
Wolfram Language. (1996). $TopDirectory. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/$TopDirectory.html