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

UNAM GPS Network - UNIP-UNIVERSUM UNAM P.S.
Start: 08-Dec-2005
End: 19-Oct-2013
Kostoglodov, Vladimir, Santiago, Jose A., 2006, UNAM GPS Network - UNIP-UNIVERSUM UNAM P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5QJ7FJ2