Zoubir F, Khan WN, Hammarström S (May 1990). "Carcinoembryonic antigen gene family members in submandibular salivary gland: demonstration of pregnancy-specific glycoproteins by cDNA cloning". Biochemical and Biophysical Research Communications. 169 (1): 203–16. doi:10.1016/0006-291X(90)91455-2. PMID2350345.
Streydio C, Lacka K, Swillens S, Vassart G (Jul 1988). "The human pregnancy-specific beta 1-glycoprotein (PS beta G) and the carcinoembryonic antigen (CEA)-related proteins are members of the same multigene family". Biochemical and Biophysical Research Communications. 154 (1): 130–7. doi:10.1016/0006-291X(88)90660-2. PMID3260773.