TY  - RPRT
TI  - Concepts for reference frames in geodesy and geodynamics - The reference directions
AU  - Grafarend, E. W.
AU  - Richter, B.
AU  - Mueller, I. I.
AU  - Papo, H. B.
PY  - 1979
UR  - https://ntrs.nasa.gov/citations/19800027347
ID  - 19800027347
ER  -