Nature. 2015 Jul 23;523(7561):486-90. doi:10.1038/nature14590

Buenrostro JD, Wu B, Litzenburger UM, Ruff D, Gonzales ML, Snyder MP, Chang HY, Greenleaf WJ.

Single-cell chromatin accessibility reveals principles of regulatory variation.

Because the data is sparse, peaks with similar properties need to be analysed as pools.