APA-referens (7:e uppl.)

Lith, J. M. M. v. (1994). First trimester screening for Down's syndrome. s.n.].

Chicago-referens (17:e uppl.)

Lith, Johannes Marinus Maria van. First Trimester Screening for Down's Syndrome. [S.l.: s.n.], 1994.

MLA-referens (8:e uppl.)

Lith, Johannes Marinus Maria van. First Trimester Screening for Down's Syndrome. s.n.], 1994.