This article states that in 1930 Skolem independently (of Presburger) published quantifier-eliminations for linear algebra over the integers.
I have checked the Ω-Bibliography of Mathematical Logic and was not able to find such a result.
According to Hao Wang's account in Skolem's selected works in logic this is also not the topic of Skolem's "Über einige Satzfunktionen in der Arithmetik" which is quoted in the article. The paper is also from 1931 not 1930.
Does anybody know about this paper of Skolem?