Nurul, M. , Shafik, H. , Maria, A. , Maria, G. (2013). 'Solvent Effect on Antioxidant Activity and Total Phenolic Content of Betula alba and Convolvulus arvensi'. World Academy of Science, Engineering and Technology, Open Science Index 77, International Journal of Biotechnology and Bioengineering, 7(5), 351 - 356.