According to the dividend discount models, the value of a share of common stock is primarily based on dividends. Does it mean that a company that does not pay dividends is worthless? What other factors must be considered in the valuation of equity and why? kindly, provide the references in order to read it form the original sources

Could you give some light on how the dividends are taxed in the hands of the investor in different countries? How do these tax policies specific to a country affect the desirability of dividends to shareholders? Please, reference for answer in order to study it from the sources