https://pt.wikipedia.org/wiki/Sistema_operativo
https://en.wikipedia.org/wiki/Operating_system
https://www.infopedia.pt/$sistema-operativo
https://pt.slideshare.net/Bugui94/sistema-operativos-presentation
https://slideplayer.com.br/slide/4083422/
https://prezi.com/ccqb2lwingpx/evolucao-historica-dos-sistemas-operativos/
https://pt.slideshare.net/KaskaLucas/evoluo-dos-sistemas-operativos-9885263
https://pt.slideshare.net/juliobita7/evoluo-dos-sistemas-operativos-33792138
https://sites.google.com/site/historiadoscomputadoress/home/hardware

história de sistema operativo:
https://www.computerhope.com/os.htm
https://pandorafms.com/blog/operating-system-history/

evolução do sistema operativo:
https://www.geeksforgeeks.org/introduction-of-operating-system-set-1/
https://sites.google.com/site/optsytms/history-of-operating-systems
https://www.supinfo.com/articles/single/4881-evolution-of-microsoft-operating-systems
https://www.brainkart.com/article/Evolution-of-Operating-System_9827/
http://www.edm2.com/index.php/Operating_System_Evolution
https://www.studytonight.com/operating-system/evolution-of-os
http://www.technologyuk.net/computing/computer-software/operating-systems/operating-system-evolution.shtml

info de datas:
https://upload.wikimedia.org/wikipedia/commons/1/1b/Linux_Distribution_Timeline.svg
https://en.wikipedia.org/wiki/List_of_Microsoft_Windows_versions
https://en.wikipedia.org/wiki/Macintosh_operating_systems