Volume 14, Issue 3 Markus Holzmann Gerhard Unger Boundary integral formulations of eigenvalue problems for elliptic differential operators with singular interactions and their numerical approximation by boundary element methods Downloads Abstract PDF Full article PDF DOI { copied = true; setTimeout(() => copied = false, 2000) })" :aria-label="copied ? 'DOI copied' : 'Copy DOI'" :title="copied ? 'Copied' : 'Copy DOI'" > Find all available articles from these authors Markus Holzmann Gerhard Unger Find more articles with the same keywords elliptic differential operators $\delta$ and $\delta'$-interaction discrete eigenvalues integral operators boundary element method Find more articles with the same subject classes 35Q40 47J10 65N38 65N25