Now I'm reading the paper of Friedrich Roesler on the representation theory of Schur-Rings with the title 'Darstellungstheorie von Schur-Algebren' (Math Z 1972).

My goal is to understand algebraic theory of the Schur-rings used in the paper of John Karlof 'The Subclass Algebra Associated with a Finite Group and Subgroup'

Is there any English reference for the paper of Friedrich Roesler?

Thank you in advance!