The Image of the Enveloping Algebra and Irreducibility of Induced Representations of Exponential Lie Groups. Jacob Jacobsen — 1995 Mathematica Scandinavica
Eigenspace representations of nilpotent lie groups. Henrik Stetkaer; Jacob Jacobsen — 1981 Mathematica Scandinavica
Ultra-irreducibility of induced representations. Henrik Stetkaer; Jacob Jacobsen — 1991 Mathematica Scandinavica