Feki Krichene, ÙÙAfef, and Walid Khoufi. “The Determinants of issuers’ Long Term Credit Ratings : American S&P500 Index”.
International Journal of Accounting and Economics Studies, vol. 3, no. 1, May 2015, pp. 78-85,
https://doi.org/10.14419/ijaes.v3i1.4631.