1. Hunting the mysterious dark photon: the NA64 experiment (CERN).
2. D. J. Kapner, T. S. Cook, E. G. Adelberger, et al., Phys. Rev. Lett., 98, 021101 (2007).
3. C. D. Hoyle, Int. J. Mod. Phys. D, 15, No. 12, 2309−2315 (2006).
4. H. B. Kasimir, Proc. Kon. Nederl. Akad. Wet., 51, 793 (1948).
5. Project CANNEX, New sensor, Netherlands, France.