TY - JOUR AU - Adam Os/ekowski TI - Sharp Ratio Inequalities for a Conditionally Symmetric Martingale JO - Bulletin of the Polish Academy of Sciences. Mathematics PY - 2010 SP - 65 EP - 77 VL - 58 IS - 1 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.4064/ba58-1-8/ DO - 10.4064/ba58-1-8 LA - en ID - 10_4064_ba58_1_8 ER -