https://catalogue-scientifique.canada.ca/record=3398404~S6*frc
Rechercher Robinson, A. H; Rechercher Timm, W. B; Rechercher Goudge, M. F; Rechercher Elworthy, R. T
1926
A review of fifteen years' progress in the production of non-metallic minerals in Canada by members of the staff of the Mineral Resources Division.
Publication gouvernementale