Z. H. Xuan & L. S. Shu. (1970). Boundedness for Commutators of Calderόn-Zygmund Operator on Morrey Spaces with Variable Exponent.
            <i>Analysis in Theory and Applications</i>. <i>29</i> (2).
            128-134.
         doi:10.4208/ata.2013.v29.n2.4