References
Pires-daSilva A, Sommer RJ. The evolution of signalling pathways in animal development. Nat Rev Genet. 2003 Jan ;4(1):39-49. PMID : 12509752
Selleck SB. Proteoglycans and pattern formation: sugar biochemistry meets developmental genetics. Trends Genet. 2000 May;16(5):206-12. PMID: 10782114