Identity matrix - Wikipedia
介绍identity matrices - CSDN博客
Identity Matrix (Unit matrix) - Definition, Properties and Examples
单位矩阵和逆矩阵 - 知乎 - 知乎专栏
Identity Matrix - What is Identity Matrix? Examples - Cuemath
2.6: The Identity and Inverses - Mathematics LibreTexts
Identity Matrix (Unit Matrix) - Definition, Properties & Examples
The identity matrix and its properties - MathBootCamps
Identity Matrix -- from Wolfram MathWorld
Identity Matrix: Definition, Properties, and Applications - StudyPug