“Achtergronden van de Hydrodynamische Excitatie”, by Peter van Oossanen, Published in “Schip en Werf”, Vol. 44, No. 17, pp. 515-524, August 1977 (ID No. 4473a).
This paper (in Dutch) addresses the origin and nature of the vibratory forces on the aft-body of the hull of ships as caused by the operating propeller.