Gas properties in the Early Universe deciphered from spectral line surveys of high-z objects: The Cloverleaf QuasarMichel Guélin, Carsten Kramer, Chentao Yang, Belén Tercero and José CernicharoEPJ Web of Conferences, 265 (2022) 00024DOI: https://doi.org/10.1051/epjconf/202226500024