Academia Scientiarum Fennica, 1975. — 154 p.
"The more important of these for the historian is without doubt that of Helen. He does not cast his net very wide (he shirks the task of interpreting the absence of brick-stamps in the mid-third century and their re-appearance after Diocletian) but does deal, for all that, with the fundamental problems of the organization of the production of bricks down to the Severan period. Brickmaking has been for much too long the last resort of those who are determined to find in the ancient world manufacturing industry analogous to that of modern times: not any longer, thanks to H." (N. Purcell)