Following several years of work , PERSON@1 from the ORGANIZATION@1 -LRB- LOCATION@1 , LOCATION@2 -RRB- and PERSON@2 from the ORGANIZATION@2 -LRB- ORGANIZATION@3 -RRB- determined the relationship between the hyperfine transition frequency of the cesium atom and the ephemeris second .

Following several years of work , PERSON@1 from the ORGANIZATION@1 -LRB- LOCATION@1 , LOCATION@2 -RRB- and PERSON@2 from the ORGANIZATION@2 -LRB- ORGANIZATION@3 -RRB- determined the relationship between the hyperfine transition frequency of the caesium atom and the ephemeris second .
