@misc{HallerDintelmannHoeppnerKaiseretal.2011, author = {Robert Haller-Dintelmann and Wolfgang H{\"o}ppner and Hans-Christoph Kaiser and G{\"u}nter M. Ziegler}, title = {Optimal elliptic Sobolev regularity near three-dimensional, multi-material Neumann vertices}, institution = {Research Center Matheon}, type = {preprintmatheon}, year = {2011}, }