The question was considered of whether Bollmann's division of triple junctions into I- and U-lines corresponded to physical reality. A virtual multiple junction of small-angle boundaries was described in 2 ways. Firstly, by using Bollmann's I/U-line scheme (Bollmann disclinations). Secondly, by using an elasticity approach (rotational Volterra cuts, Volterra disclinations). Depending upon the number of boundaries, the multiple junction was found to be an I-line or a U-line. It was concluded that the Bollmann disclination was a real crystallographic defect that was essentially different to the Volterra disclination.

Disclinations at Grain Boundary Triple Junctions - Between Bollmann Disclinations and Volterra Disclinations. P.Müllner: Materials Science Forum, 1999, 294-296, 353-6