McLachlan RI, Offen C. Hamiltonian Boundary Value Problems, Conformal Symplectic Symmetries, and Conjugate Loci. NZ J Math [Internet]. 2018 Dec. 31 [cited 2024 Apr. 19];48:83-99. Available from: https://nzjmath.org/index.php/NZJMATH/article/view/34