"The Hybrid Trebuchet: The Halfway Step to the Counterweight Trebuchet," in On the Social Origins of Medieval Institutions: Essays in Honor of Joseph F. O'Callaghan, 179–222, edited by Donald J. Kagay and Theresa M. Vann.
"The Hybrid Trebuchet: The Halfway Step to the Counterweight Trebuchet, " in On the Social Origins of Medieval Institutions: Essays in Honor of Joseph F. O’Callaghan, 179—222, edited by Donald J. Kagay and Theresa M. Vann.