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

Greenland GNSS Network - SENU-Sermip Nunataa P.S.
Start: 16-May-2008
End: 14-Nov-2022
SDFE, The Danish Agency, UNAVCO Community, Bevis, Michael, 2008, Greenland GNSS Network - SENU-Sermip Nunataa P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/NVG7-3K93

Greenland GNSS Network - SENU-Sermip Nunataa P.S.
Start: 01-Jan-2019
End: 14-Nov-2022
SDFE, The Danish Agency, 2008, Greenland GNSS Network - SENU-Sermip Nunataa P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/PS21-AG76

Greenland GNSS Network - SENU-Sermip Nunataa P.S.
Start: 16-May-2008
End: 31-Dec-2011
Bevis, Michael, 2008, Greenland GNSS Network - SENU-Sermip Nunataa P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T59C6VG9

Greenland GNSS Network - SENU-Sermip Nunataa P.S.
Start: 01-Jan-2012
End: 31-Dec-2018
UNAVCO Community, 2008, Greenland GNSS Network - SENU-Sermip Nunataa P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/QJE2-5K98