Ek P., Ek B., and Zetterqvist Örjan. “ Phosphohistidine Phosphatase 1 (PHPT1) Also Dephosphorylates Phospholysine of Chemically Phosphorylated Histone H1 and Polylysine”. Upsala Journal of Medical Sciences, vol. 120, no. 1, Jan. 2015, doi:10.3109/03009734.2014.996720.