Baur, U., Buras, A. J., Gérard, J.-M., & Ruckl, R. (1986). D0 ---> anti K0 : Annihilation form factor and 1/N expansion. Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics, 175(3), 377-382. https://doi.org/10.1016/0370-2693(86)90873-7 (Original work published 1986)