National Council of Educational Research and Training. (2017). NCERT SCIENCE: TEXT BOOK for Class IX.
استشهاد بنمط شيكاغوNational Council of Educational Research and Training. NCERT SCIENCE: TEXT BOOK for Class IX. 2017.
MLA استشهادNational Council of Educational Research and Training. NCERT SCIENCE: TEXT BOOK for Class IX. 2017.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.