Every U.P. group is a t.u.p group. See
Andrzej Strojnowski, A note on u.p. groups, Communications in Algebra, 8:3, (1980) 231-234.
- Andrzej Strojnowski, A note on u.p. groups, Communications in Algebra, 8:3, (1980) 231-234. doi:10.1080/00927878008822456