Schröder-Lang, S., Schwärzel, M., Seifert, R., Strünker, T., Kateriya, S., Looser, J., Watanabe, M., Kaupp, B., Hegemann, P., & Nagel, G. (2007). Fast manipulation of cellular cAMP level by light in vivo. Nature Methods, 4(1), 39-42.