What Is Going on with the Research into the Internationalization of Small and Medium-Sized Enterprises (SMEs)? An Intellectual Structure Analysis into the State-of-the-Art (1990-2018). - María del Pilar Casado-Belmonte; Gema María Marín-Carrillo; Eduardo Terán-Yépez; María de las Mercedes Capobianco-Uriarte (Publ., 2020)