TY  - RPRT
TI  - Multiphonon theory: Wick's theorem and recursion formulas for coupled phonons.
AU  - KV Protasov
AU  - B Silvestre-Brac
AU  - R Piepenbring
AU  - M Grinberg
PY  - 1996
DO  - 10.1103/physrevc.53.1646
UR  - https://pubmed.ncbi.nlm.nih.gov/9971114/
ID  - 9971114
ER  -