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

Geopentech GPS Network - ELLY-LongBchBayCA2013 P.S.
Start: 26-Feb-2013
End: 14-Nov-2022
Walls, Chris, 2013, Geopentech GPS Network - ELLY-LongBchBayCA2013 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5JW8BZG