Master integrals for double real radiation emission in heavy-to-light quark decay Roberto Bonciani, Alessandro Broggio, Leandro Cieri and Andrea Ferroglia Eur. Phys. J. C, 78 8 (2018) 674 Published online: 23 August 2018 DOI: 10.1140/epjc/s10052-018-6157-6