Citation
If you publish research that uses weblogo you have to cite it as follows:
Crooks, G. E., Hon, G., Chandonia, J. M., & Brenner, S. E. (2004). WebLogo: A sequence logo generator. Genome Research, 14(6), 1188-1190. https://doi.org/10.1101/gr.849004
Schneider, T. D., & Stephens, R. M. (1990). Sequence Logos: A New Way to Display Consensus Sequences. Nucleic Acids Research, 18(20), 6097-6100. https://doi.org/10.1093/nar/18.20.6097