APA (7th ed.) Citation

Marx, K. (1999). Religion as Opium: Man Makes Religion. Faith and reason, 229-229.

Chicago Style (17th ed.) Citation

Marx, Karl. "Religion as Opium: Man Makes Religion." Faith and Reason 1999: 229-229.

MLA (8th ed.) Citation

Marx, Karl. "Religion as Opium: Man Makes Religion." Faith and Reason, 1999, pp. 229-229.

Warning: These citations may not always be 100% accurate.