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

Puerto Rico GPS Network - GEOL-Geology Building UPRM P.S.
Start: 15-Sep-1996
End: 21-Oct-1999
Mattioli, Glen, Jansma, Pam, 2000, Puerto Rico GPS Network - GEOL-Geology Building UPRM P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5BR8QHZ