Adler, M., & Van Moerbeke, P. (1988). The Kowalewski and Henon-heiles Motions As Manakov Geodesic-flows On So(4) - a Two-dimensional Family of Lax Pairs. Communications in Mathematical Physics, 113(4), 659-700. https://doi.org/10.1007/BF01223242 (Original work published 1988)