no. R2
A general theorem on triangular finite C (m) -elements
Revue française d'automatique, informatique, recherche opérationnelle. Analyse numérique, Tome 8 (1974) no. R2, pp. 119-127. 
@article{M2AN_1974__8_2_119_0,
     author = {\v{Z}en{\'\i}\v{s}ek, Alexander},
     title = {A general theorem on triangular finite $C^{(m)}$-elements},
     journal = {Revue fran\c{c}aise d'automatique, informatique, recherche op\'erationnelle. Analyse num\'erique},
     pages = {119--127},
     publisher = {Dunod},
     address = {Paris},
     volume = {8},
     number = {R2},
     year = {1974},
     mrnumber = {388731},
     zbl = {0321.41003},
     language = {en},
     url = {http://www.numdam.org/item/M2AN_1974__8_2_119_0/}
}
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Ženíšek, Alexander. A general theorem on triangular finite $C^{(m)}$-elements. Revue française d'automatique, informatique, recherche opérationnelle. Analyse numérique, Tome 8 (1974) no. R2, pp. 119-127. http://www.numdam.org/item/M2AN_1974__8_2_119_0/

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