Ox is available from Timberlake Consultants.
Ox and all its components are copyright of Jurgen A. Doornik. The Console (command line) versions may be used freely for academic research and teaching purposes only; the Professional version (i.e. using OxRun/OxDebug/OxMetrics/oxli) is not free. Commercial users, academics and students who do externally funded research, and others who do not qualify for the free version must purchase the Professional version of Ox and OxMetrics with documentation, regardless of which version they use (so even when only using Ox on Linux or Unix). Failure to cite the use of Ox in published work may result in loss of the right to use the free version, and an invoice at the full commercial price.
If you redistribute modified versions of code written by me, you must change the filenames, clearly indicate the original source, and take over the responsibility of supporting that code. Only code which explicitly allows this can be redistributed in this way. Remember that often new functionality can be implemented by deriving from an existing class (instead of adjusting the base class). Redistribution of Ox in any form is not permitted. It is also not permitted to translate any Ox code that is supplied with the Ox system into another language or other code system.
The Ox syntax is public, and, of course, you may do with your own Ox code whatever you wish. If you make your code available to others, I would appreciate it if you could provide proper documentation (such as, for example, in the Arfima package). Also, try to avoid global variables: either wrap the code in a class, or hide the globals with the static keyword, providing functions to set the values.
You may not charge for any of the components which are made available by me. Contact me if you wish to distribute Ox with other products. Note that Ox is not open source; however, you can extend ox by writing dynamic link libraries that can be called from Ox.