The classical formulation of the Documentary Hypothesis posits four written sources for the Pentateuch, called J (Jahwist/Yahwist), E (Elohist), D (Deuteronomist), and P (Priestly). Since its origin, the theory has morphed into many different variations. When we try to understand the Documentary Hypothesis, we need to recognize the extensive diversity in scholarly opinion regarding how many “documents” were supposedly used to form the Pentateuch. There is also disagreement as to whether these sources are authors, editors/redactors, or “schools”—that is groups of contributors who share a single perspective.
The classical theory of Wellhausen (1883) as claims the Pentateuch was composed of four sources: JEDP. This standard four-source theory has most recently been reaffirmed by Baden (The Composition of the Pentateuch, 2012). However, many scholars disagree, developing many different models for pre-Pentateuchal sources. Cross (Canaanite Myth and Hebrew Epic, 1973) maintains that there is no P document, which was instead merely an editor, or a redactor. Rendtorff (The Problem of the Process of Transmission in the Pentateuch, 1989) argues that there is no J or E—there is only P and non-P. Van Seters (Abraham in History, 1975), believes that only J was a complete document, the other material coming from fragmentary traditions that were added later, rather than from “documents,” that is, written texts. Note the important theoretical difference between a pre-existing source, and a redactor. When you get into the details, things are even more contradictory. Are J and E two separate documents, or only one? Robert Gnuse believes there was no E (Gnuse, “Redefining the Elohist” (Journal of Biblical Literature, Vol. 119, No. 2 (Summer, 2000), pp. 201-220).
So, we have, as only a few of the different variants:
JEDP (Wellhausen and Baden)
P and non-P only (Rendtorff)
J and fragments and supplements (Van Seters)
Many of the original four sources are further divided by scholars into various sub- or pre- sources from which each distinct penultimate source of the Pentateuch was composed. Thus, the Deuteronomist is sometimes divided into Dtr1, Dtr2, DtrN, and DtrP. The legal and ritual material in the Bible are likewise divided into numerous different “Codes,” often seen as independent sources: the Holiness Code (H; Lev. 17-26), the Covenant Code (Ex. 20:19-23:33), and the Deuteronomic Code (Deut. 12-26 = DtrN).
But this is not enough. All sorts of other sources have been proposed, often with limited support: L (a lay/non-priestly source), N (nomadic source), K (a Kenite source), G (grundlage, “foundation”), and S (a southern source). To all this is finally added a plethora of Redactors (R, R1, R2, etc.) To the multiplication of sources, there is no end. One could almost argue that the ultimate lost source of the Bible is the alphabet.
On a serious note, the wide range of different proposed sources for the Bible poses a serious methodological problem. What we have as dozens of scholars—all equally informed, trained, and intelligent, and sharing the same basic assumptions and methods. Yet when applying those methods to the Bible, they cannot come to a fundamental agreement. There is far more diversity of scholarly opinions today than there has ever been. Scholars are moving away from consensus on these matters, not toward it. The only skeptical and pragmatic regarding this situation is that the theory has failed.