TY - JOUR AU - K Szymaniec AU - W Chalupczak AU - Eite Tiesinga AU - Carl Williams AU - S Weyers AU - R. Wynands C2 - Physical Review Letters DA - 2007-04-13 00:04:00 LA - en M1 - 98 PB - Physical Review Letters PY - 2007 TI - Cancellation of the Collisional Frequency Shift in Caesium Fountain Clocks ER -