ian ▁Anton y ▁F . ▁Campbell ▁says ▁source ▁criticism ' s ▁most ▁influ ential ▁work ▁is ▁Julius ▁Well hausen ' s ▁Pro leg omena ▁zur ▁Geschichte ▁Isra els ▁( Pro log ue ▁to ▁the ▁History ▁of ▁Israel , ▁ 1 8 7 8 ) ▁which ▁sought ▁to ▁establish ▁the ▁sources ▁of ▁the ▁first ▁five ▁books ▁of ▁the ▁Old ▁Testament . ▁Well hausen ▁correl ated ▁the ▁history ▁and ▁development ▁of ▁those ▁five ▁books , ▁known ▁as ▁the ▁Pent ate uch , ▁with ▁the ▁development ▁of ▁the ▁Jewish ▁faith . ▁The ▁Document ary ▁hypothesis , ▁also ▁known ▁as ▁the ▁J ED P ▁theory , ▁or ▁the ▁Well hausen ▁theory , ▁says ▁the ▁Pent ate uch ▁was ▁combined ▁out ▁of ▁four ▁separate ▁and ▁coh er ent ▁sources ▁known ▁as ▁J ▁( which ▁stands ▁for ▁Y ah w ist , ▁which ▁is ▁sp elled ▁with ▁a ▁J ▁in ▁German ), ▁E ▁( for ▁E lo h ist ), ▁D ▁( for ▁De uter onom ist ), ▁and ▁P ▁( for ▁the ▁Pri est ly ▁source ). ▁Old ▁Testament ▁scholar ▁Karl ▁Graf ▁( 1 8 1 5 – 1 8 6 9 ) ▁suggested ▁the ▁P ▁in ▁ 1 8 6 6 ▁as ▁the ▁last ▁str atum ▁of ▁the ▁Well hausen ▁theory . ▁Therefore , ▁the ▁Document ary ▁hypothesis ▁is ▁sometimes ▁also ▁referred ▁to ▁as ▁the ▁Graf – Well hausen ▁hypothesis . ▁Later ▁sch ol ars ▁infer red ▁more ▁sources , ▁with ▁increasing ▁information ▁about ▁their ▁extent ▁and ▁inter - rel ations hip . ▁ ▁The ▁fragment ary