Hypothalamic-pituitary-gonadal axis in two men with aromatase deficiency: evidence that circulating estrogens are required at the hypothalamic level for the integrity of gonadotropin negativa feedback - Rochira, V; Zirilli, L; Genazzani, A D; Balestrieri, A; Aranda, C; Fabre, B; Antunez, P; Diazzi, C; Carani, C; Maffei, L (Eur J Endocrinol, 2006)