https://www.actfl.org/advocacy/what-the-research-shows#academic_achievement https://projects.esc20.net/upload/page/0083/docs/BILChart_5.21.19.pdf https://projects.esc20.net/upload/page/0083/docs/BILChart_5.21.19_ES.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3583091/