Gauge Independence of the Lagrangian Path Integral in a Higher-Order   Formalism
  We propose a Lagrangian path integral based on gauge symmetries generated by a symmetric higher-order $\Delta$-operator, and demonstrate that this path integral is independent of the chosen gauge-fixing function. No explicit change of variables in the functional integral is required to show this. 
I.A. Batalin, K. Bering and P.H. Damgaard