@article{04097726, title = {On }, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {12}, year = {1989}, pages = {107-112}, doi = {10.1155/S0161171289000141}, zbl = {0671.30011}, language = {en}, url = {http://dml.mathdoc.fr/item/04097726} }
Chen, Ming-Po; Lan, Lh-Ren. On . International Journal of Mathematics and Mathematical Sciences, Tome 12 (1989) pp. 107-112. doi : 10.1155/S0161171289000141. http://gdmltest.u-ga.fr/item/04097726/