Embedding (R+R^2)-Inflation into Supergravity by Sergei V. Ketov and Alexei A. Starobinsky (2011)

Primary text: arxiv.org/pdf/1011.0240

Cited passages: Section I, equation(2), R+R-squared gravity/scalar representation; Section IV, equation(26), first potential term of pure R+R-squared model. Their Ricci-sign convention differs from some cosmology texts; wiki action declares its convention. Authors and affiliations verified on title page. Physical Review D83,063512(2011).