@article{JTNB_2005__17_3_925_0,
     author = {Tolev, Doychin},
     title = {On the exceptional set of {Lagrange{\textquoteright}s} equation with three prime and one almost{\textendash}prime variables},
     journal = {Journal de th\'eorie des nombres de Bordeaux},
     pages = {925--948},
     publisher = {Universit\'e Bordeaux 1},
     volume = {17},
     number = {3},
     year = {2005},
     doi = {10.5802/jtnb.528},
     zbl = {05016595},
     mrnumber = {2212133},
     language = {en},
     url = {http://www.numdam.org/articles/10.5802/jtnb.528/}
}