SHIH-I CHUWang, K.K.WangLayton, E.E.Layton2019-12-262019-12-261990https://scholars.lib.ntu.edu.tw/handle/123456789/441712Nonperturbative treatments of level shifts of excited states and high-order harmonic generation in strong fieldsjournal article10.1364/JOSAB.7.0004252-s2.0-84975629400https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975629400&doi=10.1364%2fJOSAB.7.000425&partnerID=40&md5=73a5c38bbf5574ef78f1e986e00f8d87