Sayad, B. W., & Sayad, B. W. (1997). An invitation to health: The power of prevention (7th ed.). Brooks/Cole Pub..
Cita Chicago (17th ed.)Sayad, Barbara W., i Barbara Werner Sayad. An Invitation to Health: The Power of Prevention. 7th ed. Pacific Grove, CA: Brooks/Cole Pub., 1997.
Cita MLA (8th ed.)Sayad, Barbara W., i Barbara Werner Sayad. An Invitation to Health: The Power of Prevention. 7th ed. Brooks/Cole Pub., 1997.
Atenció: Aquestes cites poden no estar 100% correctes.