@article{moloney_dickman_2006,  title={Functional-integral based perturbation theory for the Malthus-Verhulst process},  volume={36},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332006000700022},  DOI={10.1590/S0103-97332006000700022},  number={4a},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Moloney, Nicholas R. and Dickman, Ronald},  year={2006},  month={Dec},  pages={1238–1249} }