FU JIAN, GAO XIAO-CHUN, XU JING-BO, ZOU XU-BO. INVARIANT-RELATED UNITARY TRANSFORMATION METHOD AND EXACT SOLUTIONS FOR THE QUANTUM DIRAC FIELD IN A TIME-DEPENDENT SPATIALLY HOMOGENEOUS ELECTRIC FIELDJ. Acta Physica Sinica, 1999, 48(6): 1011-1022. DOI: 10.7498/aps.48.1011