TY - JOUR AU - Ping Ding TI - An improvement to Chalk's estimation of exponential sums JO - Acta Arithmetica PY - 1991 SP - 149 EP - 155 VL - 59 IS - 2 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.4064/aa-59-2-149-155/ DO - 10.4064/aa-59-2-149-155 LA - en ID - 10_4064_aa_59_2_149_155 ER -