TY  - RPRT
TI  - NIST time and frequency bulletin, no. 549 
AU  - Petty, Eyvon M
PY  - 2003
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - NIST IR 6629-09
DO  - 10.6028/NIST.IR.6629-09
ER  -