S. 153A : Assessment-Search or requisition-Settlement Commission-Assessment of third person-Double taxation-Long-term capital gains-Capital gains relating to assessee already disclosed and taxed in hands of firm, in which the assessee was partner, and accepted by Settlement Commission-Cannot be taxed again in hands of assessee. [S. 10(38), 45, 132, 153C, 245A(4), 245D]