@book{di2013algebra,
  title={Algebra},
  author={Di Martino, P. and Dvornicich, R.},
  isbn={9788867410958},
  series={Didattica e Ricerca. Manuali},
  year={2013},
  publisher={Pisa University Press}
},
@article{10.2307/2315810,
 ISSN = {00029890, 19300972},
 URL = {http://www.jstor.org/stable/2315810},
 author = {M. A. Jodeit},
 journal = {The American Mathematical Monthly},
 number = {7},
 pages = {835--836},
 publisher = {Mathematical Association of America},
 title = {Uniqueness in the Division Algorithm},
 volume = {74},
 year = {1967}
}