What is the criteria for a function to exist in an inverse of it? - Quora
How to prove that a function is invertible if and only if it is bijective - Quora
Does the usual procedure for finding the inverse function also prove that the function is invertible? - Mathematics Stack Exchange
Draw the graph of the following function and determine whether it is invertible. y = 2 x^2 + 1 / x^2 - 1 | Homework.Study.com
Class 12: Invertible Functions - YouTube
Determining if a function is invertible (video) | Khan Academy
real analysis - If $f:\mathbb{R}\to \mathbb{R}$ is an invertible function, is it necessary that the function has to be strictly monotonic? - Mathematics Stack Exchange