Title: Oka i okskoe sudokhodstvo
Subjects: Water transportation, Schifffahrt, Wassertransport, Inland water transportation, History, Steamboats, Hydraulic engineering, Hydraulic structures
Places: Oka, Russia (Federation), Oka River Valley (Kurskai͡a oblastʹ-Nizhegorodskai͡a oblastʹ), Oka River Valley (Kurskai͡a oblastʹ-Nizhegorodskai͡a oblastʹ, Russia)