On subfields of k(x)
Rendiconti del Seminario Matematico della Università di Padova, Tome 75 (1986) , pp. 257-273. 
@article{RSMUP_1986__75__257_0,
     author = {Alexandru, Victor and Popescu, Nicolae},
     title = {On subfields of $k(x)$},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {257--273},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {75},
     year = {1986},
     zbl = {0596.12027},
     mrnumber = {847671},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1986__75__257_0/}
}
Alexandru, Victor; Popescu, Nicolae. On subfields of $k(x)$. Rendiconti del Seminario Matematico della Università di Padova, Tome 75 (1986) , pp. 257-273. http://archive.numdam.org/item/RSMUP_1986__75__257_0/

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