https://www.goodtheorist.science/
https://www.susanrigetti.com/physics
https://dl.icdst.org/pdfs/files3/91fd86c3c11da17c96114187b1aebf85.pdf
https://www.coursera.org/learn/einstein-relativity
https://ocw.mit.edu/courses/8-20-introduction-to-special-relativity-january-iap-2021/
https://physics.stackexchange.com/questions/tagged/special-relativity#