Różycka-Tran, J., Jurek, P., Olech, M., Piotrowski, J., Żemojtel-Piotrowska, M. A. (2018). A Warrior Society: Data from 30 Countries show that Belief in a Zero-Sum Game is related to Military Expenditure and Low Civil Liberties. Frontiers in Psychology. DOI: 10.3389/fpsyg.2018.02645