@Article{481405,
     author = "Agnieszka Molga, Marek Wójtowicz",
     title = "Problem solving on absolute value – relevance of visualisation by means of TI-Nspire graphic calculator",
     year =  2011,
     volume =  2,
     number =  2,
     journal =  Edukacja - Technika - Informatyka,
     pages =  s. 242-252,
    }