Some examples of singularities in a free boundary
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Serie 4, Volume 4 (1977) no. 1, p. 133-144 
@article{ASNSP_1977_4_4_1_133_0,
     author = {Schaeffer, David G.},
     title = {Some examples of singularities in a free boundary},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 4},
     number = {1},
     year = {1977},
     pages = {133-144},
     zbl = {0354.35033},
     mrnumber = {516201},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1977_4_4_1_133_0}
}

Schaeffer, David G. Some examples of singularities in a free boundary. Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Serie 4, Volume 4 (1977) no. 1, pp. 133-144. http://www.numdam.org/item/ASNSP_1977_4_4_1_133_0/

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