Bianchi type string cosmological models in f(R,T) gravity P. K. Sahoo, B. Mishra, Parbati Sahoo and S. K. J. Pacif Eur. Phys. J. Plus, 131 9 (2016) 333 Published online: 23 September 2016 DOI: 10.1140/epjp/i2016-16333-x