@article {1987|1967, title = {Nesting: hierarchies of allosteric interactions}, journal = {Proc. Natl. Acad. Sci. U.s.a.}, volume = {84}, number = {7}, year = {1987}, month = {apr}, pages = {1891{\textendash}1895}, author = {Robert, C H and Decker, H and Richey, B and Gill, S J and Wyman, J} }