The direction of the dipole moments of furan,thiophen, and pyrrole: A controversial question

The report that the dipole moment in the five-membered heterocyclic rings, furan, thiophene, and pyrrole has the positive pole on the heteroatom is contradicted with arguments based on reactivity data, theoretical calculations and moment values of substituted derivatives. In actuality, the dipole moment in furan and thiophene is directed from the ring (positive pole) to the heteroatom (negative pole).