INSALL, M. (1995). POINT-VALUED MAPPINGS OF SETS. International Journal of Mathematics and Mathematical Sciences, 1995(), 819-822. https://doi.org/10.1155/S0161171295001049
PATHAK, H. K., KANG, S. M., & RYU, J. W. (1996). SOME FIXED POINTS OF EXPANSION MAPPINGS. International Journal of Mathematics and Mathematical Sciences, 1996(), 97-101. https://doi.org/10.1155/S0161171296000154