D → π and D → K semileptonic form factors with Nf = 2 + 1 + 1 twisted mass fermionsVittorio Lubicz, Lorenzo Riggio, Giorgio Salerno, Silvano Simula and Cecilia TarantinoEPJ Web Conf., 175 (2018) 13026DOI: https://doi.org/10.1051/epjconf/201817513026