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

Puerto Rico GPS Network - MIPR-Caja De Muertos Island P.S.
Start: 01-Sep-2011
End: 18-Sep-2017
Lopez, Alberto, 2011, Puerto Rico GPS Network - MIPR-Caja De Muertos Island P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5Z60MDD

Puerto Rico GPS Network - MIPR-Caja De Muertos Island P.S.
Start: 10-May-2008
End: 18-Sep-2017
Lopez, Alberto, Wang, Guoquan, 2011, Puerto Rico GPS Network - MIPR-Caja De Muertos Island P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T52Z13VX

Puerto Rico GPS Network - MIPR-Caja De Muertos Island P.S.
Start: 08-Sep-2009
End: 01-Sep-2011
Wang, Guoquan, 2011, Puerto Rico GPS Network - MIPR-Caja De Muertos Island P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5TD9VP4