APA
Horace Holley, . (1974). The World Order of Bahá'u'lláh : A Study Guide. Wilmette, IL: Baha'i Publishing Trust.
Chicago
Horace Holley, . 1974. The World Order of Bahá'u'lláh : A Study Guide. Wilmette, IL: Baha'i Publishing Trust.
Harvard
Horace Holley, . (1974). The World Order of Bahá'u'lláh : A Study Guide. Wilmette, IL: Baha'i Publishing Trust.
MLA
Horace Holley, . The World Order of Bahá'u'lláh : A Study Guide. Wilmette, IL: Baha'i Publishing Trust. 1974.