A note on the sequence ( W n ) n ≥ 0 of A. F. Horadam. Udrea, Gheorghe — 1996 Portugaliae Mathematica
Catalan's identity and Chebyshev polynomials of the second kind. Udrea, Gheorghe — 1995 Portugaliae Mathematica
A problem of Diophantos-Fermat and Chebyshev polynomials of the second kind. Udrea, Gheorghe — 1995 Portugaliae Mathematica
The diophantine equations x 2 - k = 2 · T n ( b 2 ± 2 2 ) . Udrea, Gheorghe — 1998 Portugaliae Mathematica
Chebyshev polynomials and some methods of approximation. Udrea, Gheorghe — 1998 Portugaliae Mathematica