Ferlito, Carmelo. “Disproportionality and Business Cycle from Tugan-Baranovskij to Spiethoff”. Journal of Reviews on Global Economics 4 (May 25, 2015): 108–119. Accessed December 6, 2025. https://lifescienceglobal.com/pms/index.php/jrge/article/view/3032.