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

MAGNET - PENN-PENN P.S.
Start: 17-Nov-2009
End: 26-Sep-2017
Blewitt, Geoff, Hammond, William C., Kreemer, Corne, 2011, MAGNET - PENN-PENN P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5F47MBT