Wu, C. J., Hsu, F. Y., Wen, K. L., & Wu, J. H. (2006). The Study of GM (1,1|α) on the Verhulst Model. Journal of Grey System, 9(2), 131-138. https://doi.org/10.30016/JGS.200612.0007
Li, W. O. (2007). Global motion distorts perceived shape [doctoral dissertation, The University of Hong Kong]. Airiti Library. https://www.airitilibrary.com/Article/Detail?DocID=U0029-1812201200014365