1 J.L. Hall, L.W. Hollberg, L.-S.. Ma, T.. Baer, and H.G. Robinson, Le Journal De Physique Colloques (Third Symposium on Frequency Standards and Metrology) 42, (1981).
1 J.L. Hall, L.-S.. Ma, M.S. Taubman, B.. Tiemann, F.-L.. Hong, O.. Pfister, and J.. Ye, IEEE Transactions on Instrumentation and Measurement 48, (1999).