Big-O Algorithm Complexity Cheat Sheet (Know Thy Complexities!) @ericdrowell
http://bigocheatsheet.com/algorithm - What exactly does big Ө notation represent? - Stack Overflow
https://stackoverflow.com/questions/10376740/what-exactly-does-big-%D3%A8-notation-representr/webdev - Big-O Algorithm Complexity Cheatsheet
https://www.reddit.com/r/webdev/comments/aj1dsx/bigo_algorithm_complexity_cheatsheet/