Electro-acoustic solitary waves and double layers in a quantum plasma P. R. Dip, M. A. Hossen, M. Salahuddin and A. A. Mamun Eur. Phys. J. D, 71 3 (2017) 52 Published online: 02 March 2017 DOI: 10.1140/epjd/e2017-70662-4