Zhong D., and YuanW. “Hyperbolically Lipschitz Continuity, Area Distortion and Coefficient Estimates for $(K,K′)$-Quasiconformal Harmonic Mappings of Unit Disk”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 73, no. 2, Feb. 2021, pp. 151 -59, doi:10.37863/umzh.v73i2.6041.