Bricmont, J., & Frohlich, J. (1983). AN ORDER PARAMETER DISTINGUISHING BETWEEN DIFFERENT PHASES OF LATTICE GAUGE THEORIES WITH MATTER FIELDS. Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics, B122, 73-77. https://doi.org/10.1016/0370-2693(83)91171-1 (Original work published 1983)