Unipotent blocks of finite reductive groups of a given type. Marc Cabanes, Michel Enguehard (1993) Mathematische Zeitschrift
Unipotent characters of the chevalley groups D4(q), q ODD. Meinolf Geck, Götz Pfeiffer (1992) Manuscripta mathematica
Unipotent Characters of the Sympletic and Odd Orthogonal Groups Over a Finite Field. George Lusztig (1981) Inventiones mathematicae
Untergruppenverbände zweifach transitiver Permutationsgruppen. Roland Schmidt (1975) Mathematische Zeitschrift