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

Azores GPS Network - AZGR-Graciosa P.S.
Start: 26-Jul-2008
End: 29-Jan-2017
Antunes, Marlene, Araújo, João, 2022, Azores GPS Network - AZGR-Graciosa P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/HB8T-DP49