TY  - RPRT
TI  - Optical Tracker For Longwall Coal Shearer
AU  - Poulsen, Peter D.
AU  - Stein, Richard J.
AU  - Pease, Robert E.
PY  - 1989
UR  - https://ntrs.nasa.gov/citations/19890000251
ID  - 19890000251
ER  -