Before revision: In addition, the term can take several other meanings and is also often used within e-learning and online environments.Masullo, M., Messier, P., Tsantis, L. Criscenti, D.: Agile Learning for Agile Manufacturing: An e-Learning Model; Society for Applied Learning Technology SALT'05 August 24–26, 2005 Arlington, VirginiaNoguera, Ingrid Guerrero, Anna Appel, Christine.
After revision:  Appel, Christine.