URL: https://www.factorbook.org/ 

Publications: Pratt HE, Andrews GR, Phalke N, Purcaro MJ, van der Velde A, Moore JE, Weng Z. Factorbook: an updated catalog of transcription factor motifs and candidate regulatory motif sites. Nucleic Acids Res. 2022 Jan 7;50(D1):D141-D149. doi: 10.1093/nar/gkab1039.  PMID: 34755879. 

Funding/Acknowledgements:  

NIH [U24HG009446]. Funding for open access charge: NIH [U24HG009446].