Ελευθεριάδης Ι. Μ., and Αγοραστός Κ. Α. “The Effect of Financial Leverage in Determining Business Risk”. SPOUDAI Journal of Economics and Business, vol. 52, no. 1-2, Jan. 2002, pp. 123-35, https://spoudai.org/index.php/journal/article/view/453.