-"Oil & water 1" by bitjungle is licensed under CC BY-SA 2.0
-"Resolutions and goals" by creepyed is licensed under CC BY-NC-SA 2.0
-Alkemade, F., P.H., Kelder, M., Schatorjé, C., Saynaeve, T., & Tromp, R. (2019). NOVA NaSk MAX vwo/gymnasium 1/2. ’s-Hertogenbosch, Nederland: Malmberg.