Covariant Lagrange multiplier constrained higher derivative gravity with   scalar projectors
  We formulate higher derivative gravity with Lagrange multiplier constraint and scalar projectors. Its gauge-fixed formulation as well as vector fields formulation is developed and corresponding spontaneous Lorentz symmetry breaking is investigated. We show that the only propagating mode is higher derivative graviton while scalar and vector modes do not propagate. Despite to higher derivatives structure of the action, its first FRW equation is the first order differential equation which admits the inflationary universe solution. 
Josef Kluson, Shin'ichi Nojiri and Sergei D. Odintsov
hep-th astro-ph.CO gr-qc