Lith, J. M. M. v. (1994). First trimester screening for Down's syndrome. s.n.].
Chicago Style aipamenaLith, Johannes Marinus Maria van. First Trimester Screening for Down's Syndrome. [S.l.: s.n.], 1994.
MLA aipamenaLith, Johannes Marinus Maria van. First Trimester Screening for Down's Syndrome. s.n.], 1994.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.