One-loop F(R,P,Q) gravity in de Sitter universe
  Motivated by the dark energy issue, the one-loop quantization approach for a class of relativistic higher order theories is discussed in some detail. A specific F(R,P,Q) gravity model at the one-loop level in a de Sitter universe is investigated, extending the similar program developed for the case of $F(R)$ gravity. The stability conditions under arbitrary perturbations are derived. 
Guido Cognola and Sergio Zerbini
gr-qc hep-th