Dubickas Artūras: An extended lemma of Dobrowolski and Smyth's congruence. In: Acta scientiarum mathematicarum, (77) 3-4. pp. 403-408. (2011)
Dubickas Artūras; Puriuškis Gintaras: On the minimum of certain functional related to the Schrödinger equation. (2013)