Figure 2J. Copyright: Reprinted with permission from Elsevier from [doi:10.1016/S0925-4773(99)00080-5] Mech Dev 85: 173-7, Leimeister C; Externbrink A; Klamt B; Gessler M, "Hey genes: a novel subfamily of hairy- and Enhancer of split related genes specifically expressed during mouse embryogenesis." Copyright 1999. [PMID:10415358]