Assisted dynamical Schwinger effect: pair production in a pulsed bifrequent fieldAnatoly D. Panferov, Stanislav A. Smolyansky, Andreas Otto, Burkhard Kämpfer, David B. Blaschke and Łukasz JuchnowskiEur. Phys. J. D, 70 3 (2016) 56DOI: https://doi.org/10.1140/epjd/e2016-60517-y