- Basic Knowledge on Visual SLAM From Theory to Practice by Gao Xiang et. el. - https://github.com/gaoxiang12/slambook-en (Chapter 5 Non-Linear Optimization)
- Multivariable Calculus Khan Academy - https://www.khanacademy.org/math/multivariable-calculus (Upto unit 3 for basics on multivariate differential calculus)