Applying INDIRECT function for Covariance calculus

Hi all,
I have the following problem. I have to calculate covariance of two arrays and I use the "COVAR" function fot this. But I would like to change arrays by changing starting and ending dates. I suppose I have to insert "INDIRECT" to extract data from dynamic range but I cannot do it. I will appreciate if you can help me. I enclose an example file.

Regards