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

Nepal GPS Network - AIRP-Tribhuvan International Airport P.S.
Start: 11-May-2015
End: 24-Jul-2015
Bilham, Roger G., Manadhar, Niraj, 2015, Nepal GPS Network - AIRP-Tribhuvan International Airport P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T56W98F6