Then, the stability ranking of 10 candidate genes was evaluated by ∆Ct analysis and three software programs: geNorm, NormFinder, and BestKeeper.  In addition, the results of geNorm showed that the combination of two stable RGs could make the results of gene expression more accurate. 
geNorm
Then, the stability ranking of 10 candidate genes was evaluated by ∆Ct analysis and three software programs: geNorm, NormFinder, and BestKeeper. 
NormFinder
Then, the stability ranking of 10 candidate genes was evaluated by ∆Ct analysis and three software programs: geNorm, NormFinder, and BestKeeper. 
BestKeeper
Finally, RefFinder was used to comprehensively analyze the expression stability of 10 candidate genes. 
RefFinder