  One- and two-dimensional harmonic polylogarithms, HPLs and GPLs, appear in
calculations of multi-loop integrals. We discuss them in the context of
analytical solutions for two-loop master integrals in the case of massive
Bhabha scattering in QED. For the GPLs we discuss analytical representations,
conformal transformations, and also their transformations corresponding to
relations between master integrals in the s- and t-channel.
