Cita APA (7th ed.)
Heilman, R. B., Voegelin, E., & Embry, C. R. (2004). Robert B. Heilman and Eric Voegelin: A friendship in letters, 1944-1984. University of Missouri Press.
Cita Chicago (17th ed.)
Heilman, Robert Bechtold, Eric Voegelin, i Charles R. Embry. Robert B. Heilman and Eric Voegelin: A Friendship in Letters, 1944-1984. Columbia: University of Missouri Press, 2004.
Cita MLA (9th ed.)
Heilman, Robert Bechtold, et al. Robert B. Heilman and Eric Voegelin: A Friendship in Letters, 1944-1984. University of Missouri Press, 2004.
Atenció: Aquestes cites poden no estar 100% correctes.