Textbook: "Classical Mechanics", third edition, by Goldstein, Poole and Safko
Lecture notes:
Textbook: "Mathematical Methods for Physics and Engineering", third edition
by K.F. Riley, M.P. Hobson and S.J. Bence, Cambridge University Press, Chapters 17, 18, 20, 21, 22, 28, 29
Extra lectures on Lie groups and Lie algebras
Lecture notes: