APA-viite (7. p.)
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.
Chicago-viite (17. p.)
Howell, William G., Paul E. Peterson, Patrick J. Wolf, ja David E. Campbell. The Education Gap: Vouchers and Urban Schools. Rev. ed. Washington, D.C.: Brookings Institution Press, 2006.
MLA-viite (9. p.)
Howell, William G., et al. The Education Gap: Vouchers and Urban Schools. Rev. ed. Brookings Institution Press, 2006.
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