Assaf A., Krištoufek Ladislav, Demir E., Mitra S. M. :  Market efficiency in the art markets using a combination of long memory, fractal dimension, and approximate entropy measures , JOURNAL OF INTERNATIONAL FINANCIAL MARKETS, INSTITUTIONS AND MONEY vol.71, 101312 [2021] Download Download DOI: 10.1016/j.intfin.2021.101312