Wiley D, Hilton III JL, Ellington S, Hall T. A preliminary examination of the cost savings and learning impacts of using open textbooks in middle and high school science classes. IRRODL [Internet]. 2012 Jun. 1 [cited 2024 Nov. 21];13(3):262-76. Available from: https://www.irrodl.org/index.php/irrodl/article/view/1153