CHEN CHUANG-TIAN. AN IONIC GROUPING THEORY OF THE ELECTRO-OPTICAL AND NON-LINEAR OPTICAL EFFECTS OF CRYSTALS (IV)——THE CALCULATION OF LINEAR OPTICAL SUSCEPTIBILITIES IN CRYSTALS OF THE PEROVSKITE AND THE TUNGSTEN BRONZE STRUCTURE TYPESJ. Acta Physica Sinica, 1978, 27(1): 41-46. DOI: 10.7498/aps.27.41