the formulas about isertion loss of coupled resonator filter

hi, some professor
how can i get the following formulas,

the insertion loss of the single resonator:L(f)=-10log{(1+(2QL*(f-f0)/f0)^2)/(1-(QL/QU)^2)};




the insertion loss of the filter:
L(f)=-10log{((1+QE/QU)^2/2kQE+kQE/2)^2+2((1+QE/QU)^2/k^2-QE^2)((f-f0)/f0)^2+4((QE/k)^2((f-f0)/f0)^4}

thank you!