“Enhanced superconductivity in hydrogenated potassium-mercury-graphite intercalation compounds”, G. Roth, A. Chaikin, T. Enoki, N.-C. Yeh, M. S. Dresselhaus, and P. M. Tedrow, Phys. Rev. B 32, 533 (1985).
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.32.533
https://yehgroup.caltech.edu/files/2016/07/PhysRevB.32.533-_-119.pdf