TY - JOUR AU - Sydney Geltman BT - Physics Letters A DA - Jan-01-1981 DO - 10.1016/0375-9601(81)90295-4 PY - 1981 SP - 27 EP - 30 T2 - Physics Letters A TI - Approximate response of a two-level system to intense multimode radiation VL - 81 SN - 03759601 ER -