H2B monoubiquitylation is a 5′-enriched active transcription mark and correlates with exon–intron structure in human cells - Jung, Inkyung; Kim, Seung-Kyoon; Kim, Mirang; Han, Yong-Mahn; Kim, Yong Sung; Kim, Dongsup; Lee, Daeyoup (Genome Research, 2012)