context: In 1957, he went to the United States to study at the University of California, Berkeley, and was a research assistant to Seymour Martin Lipset.
source: Etzioni is the author of over 30 books.
reference_original: Etzioni مؤلف أكثر من 30 كتاب.
reference_flipped: Etzioni مؤلفة أكثر من 30 كتاب.