Yahya Ould Hamidoune Anna S. Lladó Oriol Serra On complete subsets of the cyclic group. 1279-1285 2008 115 J. Comb. Theory, Ser. A 7 http://dx.doi.org/10.1016/j.jcta.2007.12.007 db/journals/jct/jcta115.html#HamidouneLS08