Positively and negatively charged magneto excitons in GaAs/Ga1-xAlxAs double quantum wells N. Angayarkanni, C. K. Yoo and A. John Peter Eur. Phys. J. B, 78 4 (2010) 489-496 Published online: 15 December 2010 DOI: 10.1140/epjb/e2010-10693-7