Question: when was the first iron man comic released
[{'answer': 'May 1968', 'provenance': [{'wikipedia_id': '67055', 'title': 'Iron Man', 'start_paragraph_id': 1, 'start_character': 379, 'end_paragraph_id': 1, 'end_character': 387, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]