@article{01780404, title = {Opial type }, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {30}, year = {2002}, pages = {85-95}, doi = {10.1155/S016117120201311X}, zbl = {1001.26011}, language = {en}, url = {http://dml.mathdoc.fr/item/01780404} }
Anastassiou, G.A.; Koliha, J.J.; Peǎrić, J. Opial type . International Journal of Mathematics and Mathematical Sciences, Tome 30 (2002) pp. 85-95. doi : 10.1155/S016117120201311X. http://gdmltest.u-ga.fr/item/01780404/