Céramique Couverte (céramique) Nèiménggǔ chūtǔ de Yuán qīnghuā gāo zú bēi jí qí xiāngguān wèntí 內蒙古出土的元青花高足杯及其相關問題 = Underglaze-Blue Stem Coups of the Yuan Dynasty Excavated in Inner Mongolia and Related Issues