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

Greenland GNSS Network - QAAR-Quaarsuut P.S.
Start: 01-Jan-2012
End: 31-Dec-2018
UNAVCO Community, 2008, Greenland GNSS Network - QAAR-Quaarsuut P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/TNP0-SJ65

Greenland GNSS Network - QAAR-Quaarsuut P.S.
Start: 01-Jan-2019
End: 25-Aug-2020
SDFE, The Danish Agency, 2008, Greenland GNSS Network - QAAR-Quaarsuut P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/GNQJ-0C46

Greenland GNSS Network - QAAR-Quaarsuut P.S.
Start: 28-Aug-2007
End: 31-Dec-2011
Bevis, Michael, 2008, Greenland GNSS Network - QAAR-Quaarsuut P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5PK0D6J

Greenland GNSS Network - QAAR-Quaarsuut P.S.
Start: 28-Aug-2007
End: 25-Aug-2020
SDFE, The Danish Agency, UNAVCO Community, Bevis, Michael, 2008, Greenland GNSS Network - QAAR-Quaarsuut P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/SCY8-QZ92