@article{AMI_2008_35_a14,
     author = {Ibolya Szil\'agyin\'e Szinger},
     title = {The evolvement of geometrical concepts in lower primary mathematics {(Parallel} and {Perpendicular)}},
     journal = {Annales mathematicae et informaticae},
     pages = {173--188},
     publisher = {mathdoc},
     volume = {35},
     year = {2008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AMI_2008_35_a14/}
}