APA

Cheng P., Chu D., Chueh H., See L., Chang H. & Weng D. R. (20040330). Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. : American journal of obstetrics and gynecology.

Chicago

Cheng Po-Jen, Chu Da-Chang, Chueh Ho-Yen, See Lai-Chu, Chang Hsing-Chen and Weng David Red-Helm. 20040330. Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. : American journal of obstetrics and gynecology.

Harvard

Cheng P., Chu D., Chueh H., See L., Chang H. and Weng D. R. (20040330). Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. : American journal of obstetrics and gynecology.

MLA

Cheng Po-Jen, Chu Da-Chang, Chueh Ho-Yen, See Lai-Chu, Chang Hsing-Chen and Weng David Red-Helm. Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. : American journal of obstetrics and gynecology. 20040330.