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

Africa Array GPS Network - MBEY-Mbeya Ministry of Energy and Minerals P.S.
Start: 22-Feb-2013
End: 10-Apr-2019
Nyblade, Andy, 2013, Africa Array GPS Network - MBEY-Mbeya Ministry of Energy and Minerals P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T50863C1