Colimits of representable algebra-valued functors. Bergman, George M. — 2008 Theory and Applications of Categories [electronic only]

The amalgamation basis of the category of compact groups. George M. Bergman — 1987 Manuscripta mathematica

Hyperidentities of groups and semigroups. (Short Communication). George M. Bergman — 1981 Aequationes mathematicae