2021
https://habr.com/ru/company/yandex_praktikum/blog/555704/
2019
https://habr.com/ru/company/microsoft/blog/458248/
    https://habr.com/ru/company/microsoft/blog/458242/
https://devblogs.microsoft.com/cppblog/simplify-your-code-with-rocket-science-c20s-spaceship-operator/
2018
https://brevzin.github.io/c++/2018/12/21/spaceship-for-vector/
https://blog.therocode.net/2018/12/exploring-cpp-20-three-way-comparison-aka-spaceship-operator
https://foonathan.net/blog/2018/09/07/three-way-comparison.html
https://blog.tartanllama.xyz/spaceship-operator/
https://foonathan.net/blog/2018/07/19/ordering-relations-programming.html
2015
https://arne-mertz.de/2015/01/operator-overloading-the-basics/
    https://tproger.ru/translations/cpp-operator-overload-p1/