Real representations of quivers Lidia Hügeli; Sverre Smalø — 1999 Colloquium Mathematicae The Dynkin and the extended Dynkin graphs are characterized by representations over the real numbers.
Coherent Rings and Homologically Finite Subcategories. Svein A. Sikko; Sverre O. Smalo — 1995 Mathematica Scandinavica