From which university did the 28th U.S. president earn his Ph.D.?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q30', 'id': 0, 'label': 'United States of America'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q801', 'id': 1, 'label': 'Israel'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q752297', 'id': 2, 'label': 'Doctor of Philosophy'}, {'type': 'INTERNAL', 'name_': 'Q541206', 'id': 3, 'label': 'Aviezri Fraenkel'}], 'links': [{'name_': 'P17', 'source': 0, 'target': 0, 'label': 'country'}, {'name_': 'P530', 'source': 0, 'target': 1, 'label': 'diplomatic relation'}, {'name_': 'P530', 'source': 1, 'target': 0, 'label': 'diplomatic relation'}, {'name_': 'P17', 'source': 1, 'target': 1, 'label': 'country'}, {'name_': 'P27', 'source': 3, 'target': 1, 'label': 'country of citizenship'}, {'name_': 'P512', 'source': 3, 'target': 2, 'label': 'academic degree'}]}