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

Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S.
Start: 01-Jan-2019
End: 14-Nov-2022
SDFE, The Danish Agency, 2009, Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/Q7Y8-ZX87

Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S.
Start: 01-Jan-2012
End: 31-Dec-2018
UNAVCO Community, 2009, Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/AT7R-QQ14

Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S.
Start: 12-Aug-2009
End: 31-Dec-2011
Bevis, Michael, 2009, Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5J10167

Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S.
Start: 12-Aug-2009
End: 14-Nov-2022
SDFE, The Danish Agency, UNAVCO Community, Bevis, Michael, 2009, Greenland GNSS Network - HMBG-Hamburg Gletshcer P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/6224-KD23