Hilgert J, Hofmann KH. On Sophus Lie’s Fundamental Theorem. J Funct Anal. 1986;67:1-27.

Hilgert J, Hofmann KH, Lawson JD. Controllabilty of Systems on Nilpotent Lie Groups. Beiträge Alg Geom. 1985;20:185-190.

Hilgert J, Hofmann KH. Semigroups in Lie Groups, Semialgebras in Lie Algebras. Trans AMS. 1985;288:481-504.

Hilgert J, Hofmann KH. Lorentzian Cones in Real Lie Algebras. Monatshefte Math. 1985;100:183-210.

Hilgert J, Hofmann KH. Lie Semialgebras are Real Phenomena. Math Ann. 1985;270:97-103.

Hilgert J, Hofmann KH. Old and New on SL(2). Manuscripta Math. 1985;54:17-52.

Hilgert J, Hofmann KH. Lie Theory of Semigroups. Semigroup Forum. 1984;30:243-251.