APA-ийн эшлэл(7 дахь хэвлэлт)
Strogatz, S. H., & Joffray, D. (2009). The calculus of friendship: What a teacher and a student learned about life while corresponding about math. Princeton University Press.
Чикаго-гийн эшлэл (17 дахь хэвлэлт)
Strogatz, Steven H., ба Don Joffray. The Calculus of Friendship: What a Teacher and a Student Learned About Life While Corresponding About Math. Princeton: Princeton University Press, 2009.
MLA -ийн эшлэл (9 дэх хэвлэлт)
Strogatz, Steven H., ба Don Joffray. The Calculus of Friendship: What a Teacher and a Student Learned About Life While Corresponding About Math. Princeton University Press, 2009.
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