1. Pericyclic reaction transition states: Passions and punctilios, 1935-1995;Houk;Acc. Chem. Res.,1995
2. The Conservation of Orbital Symmetry;Hoffmann,1970
3. R. Huisgen, R. Grashey, J. Sauer, Cycloaddition reactions of alkenes, The Alkenes: Volume 1 (1964), (vol. 1964) 739–953.
4. Transition structures of hydrocarbon pericyclic reactions;Houk;Angew. Chem. Int. Ed. Engl.,1992
5. Thermal Electrocyclic Reactions;Marvell,2012