de Haas-van Alphen effect and the band structure of UGe3

De Haas-van Alphen measurements, band-structure calculations, and a model of the Fermi surface are presented for U${\mathrm{Ge}}_3$. This system is representative of the $L{1}_2$ structured $\mathrm{U}{X}_3$ compounds (where $X$ is a group-III or -IV element) and is characterized as a spin-fluctuation system. Excellent agreement (considering the complications) is obtained between data and calculations. A large narrow peak in the density of states is found at the Fermi energy and is believed responsible for the nearly magnetic phenomena. Large mass enhancements are indicated. By studying U${\mathrm{Ge}}_3$, we attempt to provide some insight into the systematics of these $\mathrm{U}{X}_3$ systems.