APA-ийн эшлэл(7 дахь хэвлэлт)

Howell, W. G., Peterson, P. E., Wolf, P. J., & Campbell, D. E. (2006). The education gap: Vouchers and urban schools (Rev. ed.). Brookings Institution Press.

Чикаго-гийн эшлэл (17 дахь хэвлэлт)

Howell, William G., Paul E. Peterson, Patrick J. Wolf, ба David E. Campbell. The Education Gap: Vouchers and Urban Schools. Rev. ed. Washington, D.C.: Brookings Institution Press, 2006.

MLA -ийн эшлэл (9 дэх хэвлэлт)

Howell, William G., et al. The Education Gap: Vouchers and Urban Schools. Rev. ed. Brookings Institution Press, 2006.