Niţchi, Ştefan I. “Some Remarks about Using Heterogeneous Structures in the Computer Theory”. Rev. Anal. Numér. Théor. Approx. 21, no. 2 (August 1, 1992): 147–151. Accessed April 30, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1992-vol21-no2-art7.