Article: Richard Hagopian is perhaps the most famous artist of the traditional "kef" style and the Vosbikian Band was notable in the 1940s and 1950s for developing their own style of "kef music" heavily influenced by the popular American Big Band Jazz of the time. Later, stemming from the Middle Eastern Armenian diaspora and influenced by Continental European (especially French) pop music, the Armenian pop music genre grew to fame in the 1960s and 1970s with artists such as Adiss Harmandian and Harout Pamboukjian performing to the Armenian diaspora and Armenia; also with artists such as Sirusho, performing pop music combined with Armenian folk music in today's entertainment industry.

Question: What type of music had the biggest impact on the kef of the Vosbikian Band?
American Big Band Jazz