Question: INSPIRE-HEP, an open access digital library for the field of high energy physics developed by Stanford University, has been the main literature database for universities, colleges, and research institutions since when?
{'answer': '1970s', 'supporting_facts': [['INSPIRE-HEP', 0], ['INSPIRE-HEP', 1], ['Stanford Physics Information Retrieval System', 0], ['Stanford Physics Information Retrieval System', 1]]}