van Nieuwenhuizen (1973)Nuc.Phys.B60(1973)478 found that the only massive vector fields free of ghosts, tachyons
and higher-order poles in the propagator for linearized gravitation are the massive spin-1
Maxwell-Proca fields.

Isenberg and Nester (1977)Ann.Phys.107(1977)56 performed a Hamilton-Dirac analysis of vector fields, determining that only Maxwell fields, Proca-Maxwell fields,
and purely longitudinal vector fields are free of instability when minimally coupled to
gravity.

Moffat (2006b)JCAP03(2006)004 introduced the scalar-tensor-vector gravity (STVG) theory by including
a massive spin-1− vector phion, which is the Maxwell-Proca field, self-coupled and
coupled to a matter current, to an Einstein-Hilbert gravitational action.

In Chapter 3 of the thesis, the Maxwell-Proca field is presented in §3.4.1, and the STVG action is provided in §3.4.2. The equations of motion of a test particle are derived in §3.4.3, and the spherically symmetric point source acceleration law is derived in §3.4.4, and the Poisson equations for a test particle moving in an extended matter distribution are derived in §3.4.5. Comparison of motion in STVG is compared to the Newtonian acceleration law in §3.4.6 by means of dynamic mass measurements.