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

BARD PBO Nucleus GPS Network - JNPR-Juniper P.S.
Start: 18-Dec-1997
End: 02-Apr-2007
Romanowicz, Barbara, 2004, BARD-PBO Nucleus GPS Network - JNPR-Juniper P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5T72FS4