TY  - RPRT
TI  - Variational principle for time-dependent interactions.
AU  - SJ Ward
AU  - JH Macek
PY  - 1991
DO  - 10.1103/physreva.43.155
UR  - https://pubmed.ncbi.nlm.nih.gov/9904766/
ID  - 9904766
ER  -