Steiner, R., Osmond, D. S., & Davy, C. (1969). Knowledge of the higher worlds: How is it achieved? / by Rudolf Steiner (6th ed.). Rudolf Steiner Press.
Chicago Style (17th ed.) CitationSteiner, Rudolf, Dorothy Sophia Osmond, and C. Davy. Knowledge of the Higher Worlds: How Is It Achieved? / by Rudolf Steiner. 6th ed. London: Rudolf Steiner Press, 1969.
MLA (9th ed.) CitationSteiner, Rudolf, et al. Knowledge of the Higher Worlds: How Is It Achieved? / by Rudolf Steiner. 6th ed. Rudolf Steiner Press, 1969.
Warning: These citations may not always be 100% accurate.