  Total derivative terms play an important role in the integration of conformal
anomaly. In four dimensional space $4D$ there is only one such term, namely
$\,{\square}R$. In the case of six dimensions $6D$ the structure of surface
terms is more complicated, and it is useful to construct a basis of linear
independent total derivative terms. We briefly review the general scheme of
integrating anomaly and present the reduction of the minimal set of the surface
terms in $6D$ from eight to seven.
