P. Dondl, S. Wojtowytsch:
Uniform Regularity and Convergence of Phase-Fields for Willmore's Energy
(Submitted Paper) 2015

P. Dondl, S. Wojtowytsch:
On the Boundary Regularity of Phase-Fields for Willmore's Energy
(preprint) 2017

P. Dondl, S. Wojtowytsch:
Keeping it together: a phase field version of path-connectedness and its
  implementation
(preprint) 2018

P. Dondl, M. Novaga, S. Wojtowytsch, S. Wolff-Vorbeck:
Connected Coulomb Columns: Analysis and Numerics
Nonlinearity Vol. 34, N. 9, p. 6120-6139, 2021