  We prove continuity on domains up to the boundary for n/2-polyharmonic maps
into manifolds. Technically, we show how to adapt Helein's direct approach to
the fractional setting. This extends a remark by the author that this is
possible in the setting of Riviere's famous regularity result for critical
points of conformally invariant variational functionals. Moreover, pointwise
behavior for the involved three-commutators is established. Continuity up to
the boundary is then obtained via an adaption of Hildebrandt and Kaul's
technique to the non-local setting.
