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

PBO GPS Network - P708-YNPGrandTgWY2007 P.S.
Start: 19-Jul-2007
End: 17-Aug-2011
UNAVCO Community, 2007, PBO GPS Network - P708-YNPGrandTgWY2007 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5R78C6B