@article{DMSMF_1989_1989_1_a4,
     author = {Natkaniec, Tomasz},
     title = {Algebraic structures generated by some families of real functions.},
     journal = {Disertaciones del Seminario de Matem\'aticas Fundamentales},
     pages = {1-13},
     publisher = {mathdoc},
     volume = {6},
     year = {1989},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMSMF_1989_1989_1_a4/}
}