Genome Res. 2004 Aug;14(8):1562-74 doi:10.1101/gr.1953904

FitzGerald PC, Shlyakhtenko A, Mir AA, Vinson C.

Clustering of DNA sequences in human promoters.

Analysis of the distribution of all possible 8-mers in human proximal promoters. Identifiers 9 clusters of sequence. TATA found only in 2.6% of the promoters.