Tsuushin juyou no hensen ni kansuru jisshouteki kenkyuu : koushuu denwa 、 kanyuu denwa 、 keitai denwa no daitai o chuushin to shite

Gijutsu kakushin to denki tsuushin jiyuuka ni kansuru kenkyuu : keitai denwa o chuushin to shite

Monbu daijin o chuushin to shite hyouronseru nihon kyouiku no hensen