Extended Aperture Photometry of K2 RR Lyrae stars Emese Plachy, Péter Klagyivik, László Molnár, Ádám Sódor and Róbert Szabó EPJ Web Conf., 160 (2017) 04009 Published online: 27 October 2017 DOI: 10.1051/epjconf/201716004009