Livorni, Elvira Laura. “Classification of Algebraic Surfaces With Sectional Genus Less Than or Equal to Six. III: Ruled Surfaces With $\dim \phi_{K_X \otimes L}(X)=2$”. MATHEMATICA SCANDINAVICA 59 (June 1, 1986): 9–29. Accessed August 13, 2026. https://tidsskrift.dk/math/article/view/12150.