Towards spontaneous parametric down-conversion at low temperaturesDmitrii Akatiev, Kirill Boldyrev, Nikolai Kuzmin, Ilnur Latypov, Marina Popova, Andrey Shkalikov and Alexey KalachevEPJ Web Conf., 161 (2017) 02002DOI: https://doi.org/10.1051/epjconf/201716102002