Brandmeier, A., Börner, M., Mühlberg, T., Schulz, L., Kleinhenz, L., Endriß, T., Ellinger, S., Schmid-Ellinger, J. (2026). Education outside the classroom in Germany: An interdisciplinary multi-methods Study Protocol. PLoS ONE. https://doi.org/10.1371/journal.pone.0337524