Geodesic
On the sets A + A and A - A
Acta Universitatis Lodziensis. Folia Mathematica, Tome 05 (1992) 
Jaskuła, Janusz; Lech, Jarosław. On the sets A + A and A - A. Acta Universitatis Lodziensis. Folia Mathematica, Tome 05 (1992). http://geodesic.mathdoc.fr/item/AULFM_1992_05_a12/
@article{AULFM_1992_05_a12,
     author = {Jasku{\l}a, Janusz and Lech, Jaros{\l}aw},
     title = {On the sets {A} + {A} and {A} - {A}},
     journal = {Acta Universitatis Lodziensis. Folia Mathematica},
     year = {1992},
     volume = {05},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AULFM_1992_05_a12/}
}
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Voir la notice de l'article provenant de la source University of Lodz Repository

In the paper, an example of a closed set F of real numbers satisfying the conditions F + F = [0, 2] and F - F ≠ [-1, 1] is presented. It is a negative answer to the problem posed by M. Laczkovich. Also, some necessary condition for sets of this type is formulated.