K +→π + π 0 e + e −: a novel short-distance probeL. Cappiello, O. Catà, G. D’Ambrosio and Dao-Neng GaoEur. Phys. J. C, 72 1 (2012) 1872DOI: https://doi.org/10.1140/epjc/s10052-012-1872-x