Räbiger Frank and Ricker Werner J.: C0-semigroups and cosine families of linear operators in hereditarily indecomposable Banach spaces. In: Acta scientiarum mathematicarum, (64) 3-4. pp. 697-706. (1998)
Okada Susumu and Ricker Werner J.: Corrections to "Representation of complete Boolean algebras of projections as ranges of spectral measures". In: Acta scientiarum mathematicarum, (63) 3-4. pp. 689-693. (1997)
Okada Susumu and Ricker Werner J.: Representation of complete Boolean algebras of projections as ranges of spectral measures. In: Acta scientiarum mathematicarum, (63) 1-2. pp. 209-227. (1997)
Ricker Werner J.: Weil-bounded operators of type (B) in H.I. spaces. In: Acta scientiarum mathematicarum, (59) 3-4. pp. 475-488. (1994)