The following information obtained from UNAVCO's online DOI system:
(https://www.unavco.org/data/doi/search/search.html)

CVO GPS Network - QARY-QARY P.S.
Start: 05-Aug-2009
End: 16-Oct-2019
Lisowski, Michael, 2017, CVO GPS Network - QARY-QARY P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T51J9845