Li, S., Luceya, P. G., Milliken, R. E., Hayne, P. O., Fisher, E., Williams, J. P.,
Hurley, D. M. and Elphic, R. C. (2019). "Direct evidence of surface exposed water
ice in the lunar polar regions." Proceedings of the National Academy of Sciences,
doi: 10.1073/pnas.1802345115.
