Dubicki, Andrzej, and Tadeusz Dubicki. “The Danube As a Natural Obstacle in Romanian Army Operations”. Armia Kontra Natura, edited by Witold Jarno and Jarosław Kita, vol. 1, Lodz University Press, 2020, pp. 141-54, https://doi.org/10.18778/8220-055-3.10.