1. Axler S, Bourdon P, Ramey W. Harmonic Function Theory. Graduate Texts in Mathematics. 2nd ed. NewYork: Springer-Verlag, 2001
2. Duren P. Harmonic Mappings in the Plane. Cambridge Tracts in Mathematics, Vol 137. New York: Springer-Verlag, 1992
3. Bshouty D, Hengartner W. Univalent harmonic mappings in the plane. Ann Univ Mariae Curie-Sklodowska Sect A, 1994, 48: 12–42
4. Chen H, Gauthier P M, Hengartner W. Bloch constants for planar harmonic mappings. Proc Amer Math Soc, 2000, 128: 3231–3240
5. Chen H. The Schwarz-Pick lemma for planar harmonic mappings. Sci China Math, 2011, 54: 1101–1118