“…There are many results describing the structure of K 2 O F , see [2,[17][18][19][20][21]24] and others for the results about the 2-primary part of K 2 O F , when F is a quadratic number field. For an odd prime p, results on the p-primary part of K 2 O F can be found in [7,13,14,16,22,23], etc. In particular, some results on the 3-rank of K 2 O F were given by Browkin [4], Cheng [6], Qin and Zhou [22,23].…”