 Introduction to Celestial Mechanics by Richard Fitzpatrick

Author's book description: farside.ph.utexas.edu/Books/Celestial/Celestial.html

Online notes: farside.ph.utexas.edu/teaching/celestial/Celestialhtml/

The author's description dates the published book to 2012. Online note versions have different section numbering; locators in citations identify the consulted online section rather than claiming identical print pagination.

Elliptic orbits: farside.ph.utexas.edu/teaching/celestial/Celestialhtml/node33.html

Orbital elements: farside.ph.utexas.edu/teaching/celestial/Celestialhtml/node34.html

Jacobi integral: farside.ph.utexas.edu/teaching/celestial/Celestial/node81.html