Ia. Batalin et al., GAUGE INDEPENDENCE OF THE LAGRANGIAN PATH-INTEGRAL IN A HIGHER-ORDER FORMALISM, Physics letters. Section B, 389(4), 1996, pp. 673-676
We propose a Lagrangian path integral based on gauge symmetries genera
ted by a symmetric higher-order Delta-operator, and demonstrate that t
his path integral is independent of the chosen gauge-fixing function.
No explicit change of variables in the functional integral is required
to show this.