Radnell, David; Schippers, Eric and Staubach, Wolfgang. Quasiconformal Teichmüller theory as an analytical foundation for two-dimensional conformal field theory. In Lie algebras, vertex operator algebras, and related topics 205–238. Amer. Math. Soc., Providence, RI, 2017.
Schippers, Eric. Conformal invariants corresponding to pairs of domains. In Future trends in geometric function theory 207–219. Univ. Jyväskyl,̈ Jyv”k̈yl”a, 2003.
Radnell, David; Schippers, Eric and Staubach, Wolfgang. Quasiconformal Teichmüller theory as an analytical foundation for two-dimensional conformal field theory. In Lie algebras, vertex operator algebras, and related topics 205–238. Amer. Math. Soc., Providence, RI, 2017.
Schippers, Eric. Conformal invariants corresponding to pairs of domains. In Future trends in geometric function theory 207–219. Univ. Jyväskyl,̈ Jyv”k̈yl”a, 2003.