1968
January January ; 15 (1) : 1 - 110	March March ; 15 (2) : 111 - 226	May May ; 15 (3) : 227 - 316
July July ; 15 (4) : 317 - 422	September September ; 15 (5) : 423 - 518	November November ; 15 (6) : 519 - 653