Aubrecht, Gordon J.; French, Anthony P.; Iona, Mario; Welch, Daniel W. (February 1993). "The radian—That troublesome unit". The Physics Teacher. 31 (2): 84–87. Bibcode:1993PhTea..31...84A. doi:10.1119/1.2343667.
Aubrecht, Gordon J.; French, Anthony P.; Iona, Mario; Welch, Daniel W. (February 1993). "The radian—That troublesome unit". The Physics Teacher. 31 (2): 84–87. Bibcode:1993PhTea..31...84A. doi:10.1119/1.2343667.
Dimitrić, Radoslav M. (2012). "On Angles and Angle Measurements"(PDF). The Teaching of Mathematics. XV (2): 133–140. Archived(PDF) from the original on 2019-01-17. Retrieved 2019-08-06.
Dimitrić, Radoslav M. (2012). "On Angles and Angle Measurements"(PDF). The Teaching of Mathematics. XV (2): 133–140. Archived(PDF) from the original on 2019-01-17. Retrieved 2019-08-06.