Source: https://www.researchgate.net/profile/Peter-Bradford-4/publication/240580066_The_Blackboard_Learning_System_The_Be_All_and_End_All_in_Educational_Instruction/links/544504430cf2534c76603c96/The-Blackboard-Learning-System-The-Be-All-and-End-All-in-Educational-Instruction.pdf