I am detecting ~15 different miRNAs in serum samples. For normalization it seems most people use spike-in (cel-miR-39) or endogenous small RNA. 

I see various studies normalize to multiple endogenous or spike-in miRNAs using geotmetric mean or other methods, but I don't see any studies that actually normalize to both spike-in or endogenous small RNA. 

I want to use both spike-in and endogenous small RNA for normalization. Can this be done? Please refer me to some literature where people have done this.

Thanks,

SC