\BOOKMARK [1][-]{section.1}{1. Sextic elliptic ruled surfaces and cubic fourfolds}{}% 1 \BOOKMARK [1][-]{section.2}{2. Constructing the del Pezzo fibration}{}% 2 \BOOKMARK [1][-]{section.3}{3. Rationality of sextic del Pezzo surfaces}{}% 3 \BOOKMARK [1][-]{section.4}{4. Rationality of our cubic fourfolds}{}% 4 \BOOKMARK [1][-]{section.5}{5. Singular fibers and discriminant curves}{}% 5 \BOOKMARK [1][-]{section.6}{6. An explicit example}{}% 6 \BOOKMARK [1][-]{section*.1}{References}{}% 7