http://repository.uhamka.ac.id/id/eprint/14396/
An English Textbook Analysis: When English Rings a Bell Based on English Syllabus of 2013 Curriculum
Oktaviani N., Jihan
http://repository.uhamka.ac.id/id/eprint/14396/1/FKIP_PBI_1601055013_JIHAN%20OKTAVIANI%20N..pdf