  Let X be a proper smooth and connected surface over a finite field. We proved
in [LLR2] that the order of the Brauer group Br(X) of X is a perfect square if
it is finite. Our proof is based in part on a result of Gordon [Gor], which we
used in [LLR1] to establish a key formula. Thomas Geisser noted that the
formula in [LLR1] is incorrect, due to an omission in [Gor], and provides a
corrected formula. We explain in this corrigendum how to modify the work of
Gordon to establish a correct formula. The corrected formula can be used to
prove the result in [LLR2] without further modifications.
