Type I Shapovalov wave spacetimes in the Brans-Dicke scalar-tensor theory of gravityExact solutions for Shapovalov wave spacetimes of type
I in Brans-Dicke's scalar-tensor theory
Quadratic theory of gravity with a scalar field and type I Shapovalov wave spacetimes for gravitational-wave models in Shapovalov
I-type spacetimes, which do not arise in models of the general theory