TY  - CONF
AU  - Ortiz Bas, Angel
AU  - Andrés Romano, Carlos
AU  - Vicens Salort, Eduardo
AU  - Alemany Díaz, María Del Mar
TI  - Problems in Hierarchical Production Planning Systems with Levels presenting different Horizon and Replanning Periods
T2  - 1st World Conference on Productions and Operations Management (Sevilla, España. . 2000)
PY  - 2000
ER  -