Gehring, G. M.; Schweinsberg, A; Barsi, C; Kostinski, N; Boyd, R. W. (2006). «Observation of backward pulse propagation through a medium with a negative group velocity». Science. 312 (5775): 895–7. Bibcode:2006Sci...312..895G. PMID16690861. doi:10.1126/science.1124524
Boyd, R. W.; Chan, K. W.; O'Sullivan, M. N. (2007). «Physics. Quantum weirdness in the lab». Science. 317 (5846): 1874–5. PMID17901320. doi:10.1126/science.1148947
Gehring, G. M.; Schweinsberg, A; Barsi, C; Kostinski, N; Boyd, R. W. (2006). «Observation of backward pulse propagation through a medium with a negative group velocity». Science. 312 (5775): 895–7. Bibcode:2006Sci...312..895G. PMID16690861. doi:10.1126/science.1124524
Gehring, G. M.; Schweinsberg, A; Barsi, C; Kostinski, N; Boyd, R. W. (2006). «Observation of backward pulse propagation through a medium with a negative group velocity». Science. 312 (5775): 895–7. Bibcode:2006Sci...312..895G. PMID16690861. doi:10.1126/science.1124524
Boyd, R. W.; Chan, K. W.; O'Sullivan, M. N. (2007). «Physics. Quantum weirdness in the lab». Science. 317 (5846): 1874–5. PMID17901320. doi:10.1126/science.1148947