TY - JOUR AU - Patrick Popescu-Pampu TI - On the invariance of the semigroup of a quasi-ordinary surface singularity JO - Comptes Rendus. Mathématique PY - 2002 SP - 1101 EP - 1106 VL - 334 IS - 12 PB - Elsevier DO - 10.1016/S1631-073X(02)02404-4 LA - en ID - CRMATH_2002__334_12_1101_0 ER -