On the quiver with relations of a repetitive algebra

Let A = kQ/ár?A = kQ/\langle \rho \rangle be a finite-dimensional k-algebra where r\rho is a set of relations for the quiver Q. Assume that r\rho contains only zero-relations or commutativity-relations. We describe explicitly the quiver with relations of the repetitive algebra  of A. The following well known result of D. Happel is one of the main reasons for studying Â: If A is of finite global dimension, then the stable module category of  and the derived category of A are equivalent.