RAJ, Kuldip; SHARMA, Sunil K.; JAMWAL, Seema. SOME DOUBLE LACUNARY SEQUENCE SPACES. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 32, p. 347–358, 2014. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6207. Acesso em: 26 jul. 2026.