Gilbert, R. E., Augood, C., Gupta, R., Ades, A. E., Logan, S., Sculpher, M., & van der Meulen, J. H. P. (2001). Screening for Down's syndrome: Effects, safety, and cost effectiveness of first and second trimester strategies. BMJ Group.

Gilbert, R E., C. Augood, R. Gupta, A E. Ades, S. Logan, M. Sculpher, και J H P. van der Meulen. Screening for Down's Syndrome: Effects, Safety, and Cost Effectiveness of First and Second Trimester Strategies. BMJ Group, 2001.

Gilbert, R E., et al. Screening for Down's Syndrome: Effects, Safety, and Cost Effectiveness of First and Second Trimester Strategies. BMJ Group, 2001.