Döös, M., Wilhelmson, L., Madestam, J., & Örnberg, Åsa. (2018). The Principle of Singularity: A Retrospective Study of How and Why the Legislation Process behind Sweden’s Education Act came to Prohibit Joint Leadership for Principals. Nordic Journal of Comparative and International Education (NJCIE), 2(2-3), 39–55. https://doi.org/10.7577/njcie.2757