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

Panama GPS Network - VLCN-Volcan P.S.
Start: 18-May-2011
End: 13-Jul-2018
LaFemina, Peter, 2011, Panama GPS Network - VLCN-Volcan P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5KP806Q