TY  - RPRT
TI  - Positronium formation using the multichannel Schwinger variational principle.
AU  - U Roy
AU  - P Mandal
PY  - 1993
DO  - 10.1103/physreva.48.233
UR  - https://pubmed.ncbi.nlm.nih.gov/9909592/
ID  - 9909592
ER  -