The most fundamental influences on the composition and orchestrations in evidence throughout "Porgy and Bess", aside from those of American Jazz and Black religious music, are the European composers whose music Gershwin studied and absorbed during his tutelage with the likes of Edward Kilenyi, Rubin Goldmark, Charles Hambitzer, and Henry Cowell. Cowell's key contribution, however, may have been to suggest that Gershwin study with Joseph Schillinger, whose influence, if not as important as his followers claim, is notable throughout. Some commenters have believed they heard simililarities to melodies heard in Jewish liturgical music in Gershwin's opera. Gershwin biographer Edward Jablonski heard a similarity between the melody of "It Ain't Necessarily So" and the Haftarah blessing, while others hear similarities with Torah blessing. In a sociological survey of Jewish American culture, the author remarked, "One musicologist detected 'an uncanny resemblance' between the folk tune 'Havenu Shalom Aleichem' and the spiritual [sic 'It Take a Long Pull to Get There' from "Porgy and Bess.""