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.