@article{201111, author = {Paul Williams and Jonathan Kofler}, title = {Narrow-band measurement of differential group delay by a six-state RF phase-shift technique: 40 fs single-measurement uncertainty}, year = {2004}, number = {22}, month = {2004-02-01}, publisher = {Journal of Lightwave Technology}, url = {https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31437}, language = {en}, }