https://en.cppreference.com/w/

http://www.cplusplus.com/
http://www.cplusplus.com/reference/

https://devdocs.io/cpp/

http://eel.is/c++draft/

http://www.icce.rug.nl/documents/cplusplus/

https://msdn.microsoft.com/en-us/library/3bstk3k5(v=vs.140).aspx

offline stuff
https://zealdocs.org/
    aur/zeal, zeal-git
https://github.com/jeaye/stdman
https://github.com/freeCodeCamp/devdocs

2020
Olsson - 2020 - Cpp20 Quick Syntax Reference 4th ed
    DF925DBCB6A8C2CF646024C4FA7D3D63
2019
Lospinoso - Cpp Crash Course
    53A92F3935165F72AA4C8CD092D82B3A
2016
Zuev - Cpp Standard ru
2003
Loudon - Cpp Pocket Reference