hf for Price_to_Earnings and Price_to_Sales have a Damodaran_Method function. A reference on the method used in these functions to calculate PE and PS would be helpful. ' Prof. Damodaran (Stern School of Business at New York University) has a 'few' publications and his website has a number of models, lectures, etc. He is extremely (and thankfully) transparent on the assumptions one must test and select. It would be instructive to know which ones and what underlying assumptions are used in the hf Damodaran functions. Thank you.