On the Degree of Synchronization of kl TOL and k1 ETOL Systems. - Dietmar Wätjen; Erwin Unruh (Inf. Process. Lett., 1988)

On Extended k-uniformly-limited T0L Systems and Languages. - Dietmar Wätjen; Erwin Unruh (J. Inf. Process. Cybern., 1990)

Bitkomplexität der Maximumbestimmung in allgemeinen und speziellen Graphen. - Erwin Unruh (1990)