EinsteinAZur Quantentheorie der Strahlung [On the quantum mechanics of radiation]. Physikalische Zeitschrift1917; 18: 121–28.
2.
MaimanTHStimulated Optical Radiation in Ruby. Nature1960; 187: 493–94.
3.
TownesCHThe first laser. In: GarwinL, LincolnT (Eds). A Century of Nature: Twenty-One Discoveries that Changed Science and the World. Chicago, IL: University of Chicago Press, 2003, 107–12.
4.
GuyattGH, MillsEJ, ElbourneDIn the era of systematic reviews, does the size of an individual trial still matter?PLoS Med2008; 5: e4.