@article{JMAG_2003_10_4_a1,
     author = {Yuriy A. Aminov and Jan. L. Cie\'sli\'nski},
     title = {On the regularity of the {B\"acklund} transformation for pseudospherical surfaces},
     journal = {\v{Z}urnal matemati\v{c}eskoj fiziki, analiza, geometrii},
     pages = {469--480},
     year = {2003},
     volume = {10},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JMAG_2003_10_4_a1/}
}