Fowler, W. S., Pidcock, J., & Yorkey, R. C. Incentive themes. Book 4, teacher´s edition.
Cita Chicago (17th ed.)Fowler, W. S., J. Pidcock, i Richard C. Yorkey. Incentive Themes. Book 4, Teacher´s Edition.
Cita MLA (8th ed.)Fowler, W. S., et al. Incentive Themes. Book 4, Teacher´s Edition.
Atenció: Aquestes cites poden no estar 100% correctes.