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

Alaska Volcano Observatory GPS Network - MREP-Makushin Repeater P.S.
Start: 20-Jul-2012
End: 10-May-2019
Paskievitch, John, 2012, Alaska Volcano Observatory GPS Network - MREP-Makushin Repeater P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5P8492X