Chemical structural effects on γ-ray spectra of positron annihilation in fluorobenzenes F. Wang, X.G. Ma, L. Selvam, G.F. Gribakin and C.M. Surko Eur. Phys. J. D, 66 4 (2012) 107 Published online: 30 April 2012 DOI: 10.1140/epjd/e2012-20741-1