[1]
Roohollah, T., Hamid, R.T. and Mahdi, S. 2018. Index of difficulty which is an effective factor on especial skill formation in basketball free throw: index of learning difficulty hypothesis. Physical education of students. 22, 2 (Apr. 2018), 83-90. DOI:https://doi.org/10.15561/20755279.2018.0205.