Readers should cite both the Bio-protocol preprint and the original research article where this protocol was used:

Ramachandran, A and Hill, C(2020). Generation and LED light photoactivation of Opto-receptors. Bio-protocol Preprint. bio-protocol.org/prep281.
Ramachandran, A., Vizán, P., Das, D., Chakravarty, P., Vogt, J., Rogers, K. W., Müller, P., Hinck, A. P., Sapkota, G. P. and Hill, C. S.(2018). TGF-β uses a novel mode of receptor activation to phosphorylate SMAD1/5 and induce epithelial-to-mesenchymal transition. eLIFE. DOI: 10.7554/eLife.31756