W. Fontana. Proc. Workshop on Artificial Life (ALIFE '90), volume 5 of Santa Fe Institute Studies in the Sciences of, page 159--210. Redwood City, CA, USA, Addison-Wesley, (1992)
C. Kaleta, F. Centler, and P. Dittrich. 34, page 117-124. Humana Press, (October 2006)Proceedings of the 7 th Conference on Protein Expression in Animal Cells(PEACe).