Kin-Yiu Wong. (2020). Review of Feynman's Path Integral in Quantum Statistics: From the Molecular Schrödinger Equation to Kleinert's Variational Perturbation Theory.
            <i>Communications in Computational Physics</i>. <i>15</i> (4).
            853-894.
         doi:10.4208/cicp.140313.070513s