Key points are not available for this paper at this time.
Metric theories of gravity are compiled and classified according to the types of gravitational fields they contain, and the modes of interaction among those fields. The gravitation theories considered are classified as (i) general relativity, (ii) scalar-tensor theories, (lii) conformally flat theories, and (iv) stratified theories ith conformally flat space slices. The post-Newtonian limit of each theory is constructed and its Parametrixed Post-Newtonian (PPN) values are obtained by comparing it with Will's version of the formalism. Results obtained here, when combined with experimental data and with recent work by Nordtvedt and Will and by Ni, show that, of all thieeors thus far examined by our group, the only currently viable ones are general relativity, the Bergmann-Wagoner scalar-tensor theory and its special cases (Nordtvedt; Brans-Dicke-Jordan), and a recent, new vector-tensor theory by Nordtvedt, Hellings, and Will.
Wei-Tou Ni (Fri,) studied this question.