TY  - RPRT
TI  - Solid-state masers without inversion: Theoretical prediction for high-efficiency oscillators or phase-sensitive detectors.
AU  - FF Popescu
PY  - 1993
DO  - 10.1103/physrevb.48.13569
UR  - https://pubmed.ncbi.nlm.nih.gov/10007755/
ID  - 10007755
ER  -