TY  - RPRT
TI  - Extended coupled-cluster method. II. Excited states and generalized random-phase approximation.
AU  - JS Arponen
AU  - RF Bishop
AU  - E Pajanne
PY  - 1987
DO  - 10.1103/physreva.36.2539
UR  - https://pubmed.ncbi.nlm.nih.gov/9899158/
ID  - 9899158
ER  -