Tho, Nguyen Xuan (2021) The Diophantine equation x² + 3ᵃ · 5ᵇ · 11ᶜ · 19ᵈ = 4yⁿ Annales Mathematicae et Informaticae (54.). pp. 121-139. ISSN 1787-6117 (Online)
Tho, Nguyen Xuan (2021) What positive integers n can be presented in the form n = (x + y + z)(1/x + 1/y + 1/z)? Annales Mathematicae et Informaticae (54.). pp. 141-146. ISSN 1787-6117 (Online)