SBL citation style

Book with two or three authors

SBL reference - 6.2.2

First footnote

4. James M. Robinson and Helmut Koester, Trajectories through Early Christianity (Philadelphia: Fortress, 1971), 237.

Subsequent footnote

12. Robinson and Koester, Trajectories through Early Christianity, 23.

Bibliography

Robinson, James M., and Helmut Koester. Trajectories through Early Christianity. Philadelphia: Fortress, 1971.