Open Source Half Life - sgml/signature GitHub Wiki http://www.dtic.mil/docs/citations/ADA530179 http://www.dtic.mil/docs/citations/ADA632317 https://en.wikipedia.org/wiki/Category:Cross-platform_free_software https://registry.opendata.aws/gdelt/ https://lucumr.pocoo.org/2017/6/5/diversity-in-technology/