The 19th century scholars saw these sources as independent documents which had been carefully edited together, and for most of the 20th century this was the accepted consensus. But in 1973 the American biblical scholar Frank Moore Cross published an influential work called "Canaanite Myth and Hebrew Epic", in which he argued that P was not an independent document (i.e., a written text telling a coherent story with a beginning, middle and end), but an editorial expansion of another of the four sources, the combined Jahwist/Elohist (called JE). Cross's study was the beginning of a series of attacks on the documentary hypothesis, continued notably by the work of Hans Heinrich Schmid ("The So-called Jahwist", 1976, questioning the date of the Jahwistic source), Martin Rose (1981, proposing that the Jahwist was composed as a prologue to the history which begins in Joshua), and Van Seters ("Abraham in History and Tradition", proposing a 6th-century BCE date for the story of Abraham, and therefore for the Jahwist). Even more radical was Rolf Rendtorff ("The Problem of the Process of Transmission in the Pentateuch", 1989), who argued that neither the Jahwist nor the Elohist had ever existed as sources but instead represented collections of independent fragmentary stories, poems, etc.