@article{04105548, title = {On Baica's trigonometric identity.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {12}, year = {1989}, pages = {119-122}, doi = {10.1155/S0161171289000165}, zbl = {0675.42002}, language = {en}, url = {http://dml.mathdoc.fr/item/04105548} }
Gregorac, R.J. On Baica's trigonometric identity.. International Journal of Mathematics and Mathematical Sciences, Tome 12 (1989) pp. 119-122. doi : 10.1155/S0161171289000165. http://gdmltest.u-ga.fr/item/04105548/