Kopczynski, C.C., Alton, A.K., Fechtel, K., Kooh, P.J., Muskavitch, M.A. (1988). Delta, a Drosophila neurogenic gene, is transcriptionally complex and encodes a protein related to blood coagulation factors and epidermal growth factor of vertebrates.
Genes Dev. 2(12b): 1723--1735.