@article{JGG_2018_22_1_JGG_2018_22_1_a12,
     author = {D. Okada and T. Matsuura },
     title = {Japanese {Astronomy} {Curriculum} in {Schools} and the {Spatial} {Cognitive} {Ability} of {Elementary} and {Junior} {High} {School} {Students}},
     journal = {Journal for geometry and graphics},
     pages = {139--147},
     publisher = {mathdoc},
     volume = {22},
     number = {1},
     year = {2018},
     url = {http://geodesic.mathdoc.fr/item/JGG_2018_22_1_JGG_2018_22_1_a12/}
}