APA

Schnapp C., Alcalde J. L., Walton R., Sáez R., Concha J., Ampuero G., Parada M. & Guiloff E. (19811221). [Gestational age and real-time echography. I. Analysis of crown-rump length and parietal diameter in the first 2 trimesters of pregnancy]. : Revista chilena de obstetricia y ginecologia.

Chicago

Schnapp C, Alcalde J L, Walton R, Sáez R, Concha J, Ampuero G, Parada M and Guiloff E. 19811221. [Gestational age and real-time echography. I. Analysis of crown-rump length and parietal diameter in the first 2 trimesters of pregnancy]. : Revista chilena de obstetricia y ginecologia.

Harvard

Schnapp C., Alcalde J. L., Walton R., Sáez R., Concha J., Ampuero G., Parada M. and Guiloff E. (19811221). [Gestational age and real-time echography. I. Analysis of crown-rump length and parietal diameter in the first 2 trimesters of pregnancy]. : Revista chilena de obstetricia y ginecologia.

MLA

Schnapp C, Alcalde J L, Walton R, Sáez R, Concha J, Ampuero G, Parada M and Guiloff E. [Gestational age and real-time echography. I. Analysis of crown-rump length and parietal diameter in the first 2 trimesters of pregnancy]. : Revista chilena de obstetricia y ginecologia. 19811221.