Let p be a prime number, F a number field, and H n F the set of all unramified cyclic extensions over F of degree p having a relative normal integral basis. When ζ p ∈ F × , Childs determined the set H n F in terms of Kummer generators. When p = 3 and F is an imaginary quadratic field, Brinkhuis determined this set in a form which is, in a sense, analogous to Childs's result. The paper determines this set for all p > 3 and F with ζ p ∈ F × (and satisfying an additional condition), using the result of Childs and a technique developed by Brinkhuis. Two applications are also given.