Potrykus, Marcin. 2019. “ASSESSMENT OF GOLD AND/OR CRUDE OIL AS INVESTMENTS FOR PORTFOLIO DIVERSIFICATION. A WARSAW STOCK EXCHANGE CASE STUDY”. Acta Scientiarum Polonorum. Oeconomia 18 (4), 77-84. https://doi.org/10.22630/ASPE.2019.18.4.47.