Number - one ▁singles ▁in ▁New ▁Zealand ▁Category : T ributes ▁to ▁the ▁Beat les ▁Category : S ongs ▁written ▁by ▁A aqu il ▁Brown ▁Category : Music ▁mem es ▁Category : B ill board ▁Hot ▁R & B / H ip - H op ▁Songs ▁number - one ▁singles ▁Category : B ill board ▁Hot ▁Rap ▁Songs ▁number - one ▁singles <0x0A> </s> ▁Cla us ▁W ellen re uther ▁( born ▁ 1 9 3 5 ▁in ▁Mann heim ) ▁is ▁a ▁German ▁entrepr ene ur ▁and ▁co - found er ▁of ▁software ▁company ▁S AP ▁SE . ▁ ▁Career ▁W ellen re uther ▁studied ▁business ▁administration ▁at ▁University ▁of ▁Mann heim ▁with ▁a ▁special ization ▁in ▁operations ▁research . ▁ ▁He ▁submitted ▁his ▁dis sert ation ▁on ▁Mark ov ▁processes ▁and ▁their ▁implementation ▁on ▁queue ing ▁systems ▁in ▁ 1 9 6 8 . ▁After wards ▁W ellen re uther ▁worked ▁at ▁IBM ▁in ▁Mann heim , ▁where ▁he ▁was ▁responsible ▁for ▁developing ▁financial ▁account ancy ▁systems . ▁In ▁ 1 9 7 1 ▁he ▁left ▁IBM ▁to ▁program ▁a ▁ ▁standard ▁financial ▁account ancy ▁system ▁with ▁batch ▁processing . ▁He ▁then ▁joined ▁his ▁former ▁IBM ▁colle agues ▁H asso ▁Pl att ner , ▁Diet mar ▁Ho pp , ▁Hans - W erner ▁H ector ▁and ▁Klaus ▁Tsch ira ▁to ▁found ▁the ▁software ▁company ▁System e , ▁An wend ungen ▁und ▁Produ kte ▁in ▁der ▁Daten ver arbeit ung ▁in ▁Wein heim , ▁which ▁would ▁later ▁become ▁the ▁S AP ▁AG