Jukskul?

The family name of Russian Юкскюль was never written as Jukskul or Ükskül. There are many Latin variations (German, Sweden, Estonian etc.) but most popular are these formats: Uexküll, Uexkull, Uxkull, Yxkull, Uexkuell, Ukskull, Üksküll, Uxküll, Üexküll, Üxkull

@Lauri Kreen
Замечание учтено. В немецком языке сочетание букв "UE" равнозначно "Ü".
The remark is considered. In German language the combination of letters "UE" is equivalent "Ü".

"немецком языке сочетание букв "UE" равнозначно "Ü"" - Correct, but in some cases this (without ü) was special style to fit also into Latin texts.