A Comparison of Achievement in Technical Drawing of Students Enrolled in the Nigeria Certificate of Education (Technical) at the Kaduna Polytechnic, Kuduna, Nigeria, dissertation, August 1986; (https://digital.library.unt.edu/ark:/67531/metadc330686/m1/1/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .