The standard format for citing use of Inquisit in journal references is
Inquisit X [Computer software]. (YYYY). Retrieved from https://www.millisecond.com.
where X is the major version number and YYYY is the release year. The full version number and release year can be found by selecting the "About Inquisit..." command from the Inquisit Lab Help menu.
For example, Inquisit 5.0.11 would be cited as follows:
Inquisit 5 [Computer software]. (2016). Retrieved from https://www.millisecond.com.
The citation for Inquisit 4.0.8 is:
Inquisit 4 [Computer software]. (2015). Retrieved from https://www.millisecond.com.
The citation for the Inquisit 5 Iowa Gambling Task is:
Millisecond Software (2015). Inquisit 5 Iowa Gambling Task [Computer software]. Retrieved from https://www.millisecond.com.