Add a reference to an article.

diff --git a/doc/doxygen/references.bib b/doc/doxygen/references.bib
index 286b2e25948793113fb7a0365cf3899017c756fa..966ff103f68c9af2c66b443a7a92fe771481e8e2 100644 (file)
--- a/doc/doxygen/references.bib
+++ b/doc/doxygen/references.bib
@@ -2206,3 +2206,15 @@
   title = {A Uniform Additive {S}chwarz Preconditioner for High-Order Discontinuous {G}alerkin Approximations of Elliptic Problems},
   journal = {Journal of Scientific Computing}
 }
+
+@article{Engelman1982,
+  author = { Engelman, M. S. and Sani, R. L. and Gresho, P. M. },
+  title = { The implementation of normal and/or tangential boundary conditions in finite element codes for incompressible fluid flow },
+  journal = { Int. J. Numer. Meth. Fluids },
+  year = { 1982 },
+  volume = { 2 },
+  issue = { 3 },
+  pages = { 225--238 },
+  doi = {10.1002/fld.1650020302},
+  url = {http://doi.org/10.1002/fld.1650020302},
+}

diff --git a/include/deal.II/numerics/vector_tools_constraints.h b/include/deal.II/numerics/vector_tools_constraints.h
index 99445c9b00353f00df8324b5b74bef949ac588a7..ab4cc0d6c5fda47f34d079e5b9810340e2b55510 100644 (file)
--- a/include/deal.II/numerics/vector_tools_constraints.h
+++ b/include/deal.II/numerics/vector_tools_constraints.h
@@ -270,6 +270,13 @@ namespace VectorTools
    * at some points on the boundary is an artifact of the way it is created,
    * it is not constrained to be zero at these points.
    *
+   *
+   * <h4>Further reading</h4>
+   *
+   * A description of some of the techniques used in this function,
+   * along with a discussion of difficulties encountered with this
+   * kind of boundary conditions can be found in @cite Engelman1982 .
+   *
    * @ingroup constraints
    *
    * @see
@@ -391,6 +398,13 @@ namespace VectorTools
    * VectorTools::compute_no_normal_flux_constraints(), and leaves the one
    * component unconstrained that is constrained by that function.
    *
+   *
+   * <h4>Further reading</h4>
+   *
+   * A description of some of the techniques used in this function,
+   * along with a discussion of difficulties encountered with this
+   * kind of boundary conditions can be found in @cite Engelman1982 .
+   *
    * @ingroup constraints
    *
    * @see