@article{AUPCDM_2019_11_1_a7,
     author = {Pogonowski, Jerzy},
     title = {Remarks on the {Principle} of {Permanence} of {Forms}},
     journal = {Annales Universitatis Paedagogicae Cracoviensis. Studia ad Didacticam Mathematicae Pertinentia},
     pages = {127--141},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPCDM_2019_11_1_a7/}
}