APA (7th ed.) Citation

I︠A︡glom, A. M., I︠A︡glom, I. M., & Gordon, B. (1987). Challenging mathematical problems with elementary solutions. Dover.

Chicago Style (17th ed.) Citation

I︠A︡glom, A. M., I. M. I︠A︡glom, and Basil Gordon. Challenging Mathematical Problems with Elementary Solutions. New York: Dover, 1987.

MLA (9th ed.) Citation

I︠A︡glom, A. M., et al. Challenging Mathematical Problems with Elementary Solutions. Dover, 1987.