Irwin, K. L., Rosero Bixby, L., Oberle, M. W., Lee, N. C., Whatley, A. S., Fortney, J. A., & Bonhomme, M. G. (1988). Oral Contraceptives and Cervical Cancer Risk in Costa Rica: Detection Bias or Causal Association.

Irwin, Kathleen L., Luis Rosero Bixby, Mark W. Oberle, Nancy C. Lee, Anne S. Whatley, Judith A. Fortney, y Michele G. Bonhomme. Oral Contraceptives and Cervical Cancer Risk in Costa Rica: Detection Bias or Causal Association. 1988.

Irwin, Kathleen L., et al. Oral Contraceptives and Cervical Cancer Risk in Costa Rica: Detection Bias or Causal Association. 1988.