In the field of biblical literature his scholarly speciality was mainly the Sayings of the Historical Jesus, the Q-Document,[REF] the Pauline theology,[REF] and the theology of Liturgy and Eucharist [REF].
Ηis contribution to the Synoptic (Q) scholarship was mainly his widely accepted and used procedural principles for the reconstruction of the Q-Document[REF] and the consequences of the Q Hypothesis, not so much as a solution to the Synoptic Problem, but as a change of the conventional picture of Christian origins.