TURKISH JOURNAL OF MATHEMATICS, vol.31, no.2, pp.207-220, 2007 (SCI-Expanded)
Let lambda = 2 cos pi/5 and let H-5 be the Hecke group associated to A. In this paper, the normalizers of the congruence subgroups H-0(5)(I) in PSL(2,Z[lambda]) are studied in the case where I = (2)I-alpha', (2,I') = 1 and I' is a prime ideal.