Question: when did the cowboys come into the nfl
[{'answer': '1960', 'provenance': [{'wikipedia_id': '8121', 'title': 'Dallas Cowboys', 'start_paragraph_id': 4, 'start_character': 11, 'end_paragraph_id': 4, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '8121', 'title': 'Dallas Cowboys', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1365, 'bleu_score': 0.867886059116572, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9914509037187887015}, 'section': 'Section::::Abstract.'}]}]