Friedman, Maurice and Pat Boni eds. Martin Buber and the Human Sciences. New York: State University of New York Press, 1996.
Moore, Donald J. Martin Buber: Prophet of Religious Secularism. New York: Fordham University Press, 1996.
Schmidt, Gilya Gerda. Martin Buber's Formative Years: From German Culture to Jewish Renewal, 1897–1909. Alabama: University of Alabama Press, 1995.
Relations are not either / or, but varry in degree. The closer one comes to a genuine I-You relationship, the more likely one is drawn to service, and increasing I-You relationships.