Ly phenotypes and MHC recognition: the allohelper that recognizes K or D is a mature Ly123 cell.
Swain SL, Bakke A, English M, Dutton RW. Ly phenotypes and MHC recognition: the allohelper that recognizes K or D is a mature Ly123 cell. J Immunol. 1979 Dec; 123(6):2716-24.