On additive generalisation of Voronoi's theory of perfect forms over algebraic number fieldsLeibak, Alar2006 https://www.ester.ee/record=b2208763*est Some classes of finite 2-groups and their endomorphism semigroups = Mõnedest lõplike 2-rühmade klassidest ja nende endomorfismipoolrühmadestTamberg, Tatjana2012 https://www.ester.ee/record=b2756572*est