Hedgehog signaling in the neural crest cells regulates the patterning and growth of facial primordia.
Jeong J, Mao J, Tenzen T, Kottmann AH, McMahon AP. Hedgehog signaling in the neural crest cells regulates the patterning and growth of facial primordia. Genes Dev. 2004 Apr 15; 18(8):937-51.