Duffin-Kemmer-Petiau equation with nonminimal coupling to curvature
  The generalized Duffin-Kemmer-Petiau equation in curved space-time is proposed for non-minimal coupling to the curvature and external fields. The corresponding scalar and vector fields equation are found. Equations are presented, which are equivalent to those of a scalar field with conformal coupling and electromagnetic field with non-minimal coupling to the curvature. The gauge-invariant Duffin-Kemmer-Petiau equation with non-minimal coupling is given. 
Yu. V. Pavlov