1991
January January; 72 (1): 1 - 135	February February; 72 (2S): S1 - S355	March March; 72 (3): 275 - 420
April April; 72 (4): 421 - 570	May May; 72 (5): 571 - 722	June June; 72 (6): 723 - A40
July July; 73 (1): 1 - 104	August August; 73 (2): 105 - 242	September September; 73 (3): 243 - 372
October October; 73 (4): 373 - 512	November November; 73 (5): 513 - 679	December December; 73 (6): 681 - 859