McLachlan, Robert I, and Christian Offen. “Hamiltonian Boundary Value Problems, Conformal Symplectic Symmetries, and Conjugate Loci”. New Zealand Journal of Mathematics 48 (December 31, 2018): 83–99. Accessed November 24, 2024. https://nzjmath.org/index.php/NZJMATH/article/view/34.