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

Afar GPS Network - BHAL-Bahal Addu CGPS Station P.S.
Start: 02-Apr-2009
End: 22-Oct-2009
Calais, Eric, 2009, Afar GPS Network - BHAL-Bahal Addu CGPS Station P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5X928C9