Baltuška, A., Udem, T., Uiberacker, M., Hentschel, M., Goulielmakis, E., Gohle, C., et al. (2003). Attosecond control of electronic processes by intense light fields. Nature, 421(6923), 611-615. Retrieved from http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v421/n6923/abs/nature01414_fs.html.