Please discuss the constrains and simplifications of (Discounted Cash Flow) DCF - stock valuation models based on dividends or free cash flow. Please consider reliability of data, business cycles, dividend policy, investment horizon and investors preferences, as well. Resort to the provided Excel spreadsheet examples (included in the textbook, Ch13, spreadsheet 13.1 p. 410, spreadsheet 13.2 p. 420) and support your statements with numerical explanations derived from the available examples. Please refer to the peer-reviewed journal papers to provide thorough inside into the problems discussed.