Darlison, M. G., & Richter, D. (1999). The ‘Chicken and Egg’ Problem of Co-evolution of Peptides and Their Cognate Receptors: Which Came First?. In D. Richter (Ed.), Regulatory Peptides and Cognate Receptors (1-11). Springer. https://doi.org/10.1007/978-3-540-49421-8_1