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

Slide Mountain Tie GPS Network - SLI4-Slide Mountain Tie P.S.
Start: 16-Jun-2004
End: 29-Jun-2009
Wernicke, Brian P., 2004, Slide Mountain Tie GPS Network - SLI4-Slide Mountain Tie P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5DN43G4