@article{davidson_2009,  title={Can future systemic financial risks be quantified?: ergodic vs nonergodic stochastic processes},  volume={29},  ISSN={0101-3157},  url={https://doi.org/10.1590/S0101-31572009000400001},  DOI={10.1590/S0101-31572009000400001},  number={4},  journal={Brazilian Journal of Political Economy},  publisher={Centro de Economia Política},  author={Davidson, Paul},  year={2009},  month={Oct},  pages={324–340} }