title: Theory of Rotation for the Planet Mercury.
abstract: The theory of the rotation of the planet Mercury is developed in terms of the motion of a rigid system in an inverse-square field. It is possible for Mercury to rotate with a period exactly two-thirds of the period of revolution; there is a libration with a period of 25 years.
authors.forename: H S
authors.initials: HS
authors.lastname: Liu
authors.forename: J A
authors.initials: JA
authors.lastname: O'keefe