Goldstone, J. A., and E. Garmire. "Intrinsic optical bistability in nonlinear media". Physical review letters 53.9 (1984): 910. https://doi.org/10.1103/PhysRevLett.53.910
Sharif, Morteza A., et al. "Difference Frequency Generation-based ultralow threshold Optical Bistability in graphene at visible frequencies, an experimental realization". Journal of Molecular Liquids 284 (2019): 92–101. https://doi.org/10.1016/j.molliq.2019.03.167