@string{ABHMS = "Abh. Math. Sem. Univ. Hamburg"}
@article{Ni71,
	Author = {J. Nitsche},
	Date-Added = {2015-09-30 12:41:34 +0000},
	Date-Modified = {2015-09-30 12:46:36 +0000},
	Doi = {10.1007/BF02995904},
	Journal = ABHMS,
	Keywords = {FEM,interior penalty,DGM},
	Pages = {9–15},
	Title = {Über ein {V}ariationsprinzip zur {L}ösung von {D}irichlet-{P}roblemen bei {V}erwendung von {T}eilräumen, die keinen {R}andbedingungen unterworfen sind},
	Volume = {36},
	Year = {1971}
	}
@book {Ho03,
    AUTHOR = {Hörmander, Lars},
     TITLE = {The analysis of linear partial differential operators. {I}},
    SERIES = {Classics in Mathematics},
      NOTE = {Distribution theory and Fourier analysis,
              Reprint of the second (1990) edition [Springer, Berlin;
              MR1065993 (91m:35001a)]},
 PUBLISHER = {Springer-Verlag},
   ADDRESS = {Berlin},
      YEAR = {2003},
     PAGES = {x+440},
      ISBN = {3-540-00662-1},
   MRCLASS = {35-02},
  MRNUMBER = {1996773}
 }