http://www.databreachtoday.com/notpetya-patient-zero-ukrainian-accounting-software-vendor-a-10080

http://blog.talosintelligence.com/2017/07/the-medoc-connection.html?m=1

http://www.databreachtoday.com/police-seize-backdoored-firms-servers-to-stop-attacks-a-10083

https://www.bleepingcomputer.com/news/security/m-e-doc-software-was-backdoored-3-times-servers-left-without-updates-since-2013/

https://www.wired.com/story/petya-plague-automatic-software-updates/

https://www.theregister.co.uk/2017/06/28/petya_notpetya_ransomware/https://apnews.com/962db1cd370d4fdda6083d064b94dd1b

https://infosec.engineering/notpetya-complex-attacks-and-the-fog-of-war/