1991
January January; 61 (1): 1 - 60	February February 1991; 61 (2): 61 - 122	March March; 61 (3): 123 - 184
April April; 61 (4): 185 - 246	May May; 61 (5): 247 - 307	June June; 61 (6): 309 - 370
July July; 61 (7): 371 - 432	August August; 61 (8): 433 - 494	September September; 61 (9): 495 - 556
October October; 61 (10): 557 - 617	November November; 61 (11): 619 - 696	December December; 61 (12): 697 - 776