$\begin{array}{1 1}-\Delta T_f=K_fm\;with\;K_f=M_1RT_f^{*2}/\Delta_{fus}H_m\\-\Delta T_f=K_fm\;with\;K_f=RT_f^{*2}/M_1\Delta_{fus}H_m\\-\Delta T_f=K_fm\;with\;K_f=M_1T_f^{*2}/R\Delta_{fus}H_m\\-\Delta T_f=K_fm\;with\;K_f=\Delta_{fus}H_m/M_1RT_f^{*2}\end{array} $