↑"Few foreigners know that in fact 'the Ruhr' is the name of a 150-mile-long Rhine right-bank tributary which, after meandering through the industrial basin now named after it, enters its parent near Europe's greatest inland port, Duisburg." See German International, Volume 10 (1966), p. 30. "The territory through which the Ruhr flows is called the Ruhr district." See Edmund Jan Osmańczyk and Anthony Mango, Encyclopedia of the United Nations and International Agreements: A to F, 2003, p.1970. "Many industries were built in the Ruhr region, where both iron ore and coal were found." Kathryn Lane, Germany: The Land (2001), გვ. 24.