Nilpotente Liesche Gruppen haben symmetrische Gruppenalgebren. Detlev Poguntke (1977) Mathematische Annalen
Noncommutative uniform algebras Mati Abel, Krzysztof Jarosz (2004) Studia Mathematica We show that a real Banach algebra A such that ||a²|| = ||a||² for a ∈ A is a subalgebra of the algebra C ℍ ( X ) of continuous quaternion-valued functions on a compact set X.