Mongolyn tu̇u̇khiĭn sudalgaany shinė khandlaga, tulgamdsan asuudalCh Dashdavaa, Hiroki Oka · First published 2009Open the Tome
Tōhoku AjiaMusashi Tachikawa, Yoshinori Yasuda, Hiroki Oka, Kiyotaka Sakaida, Shirō Sasaki · First published 2009Open the Tome
1911 ony Mongolyn ẏndėsniĭ khuvʹsgalyn urʹdkhilsan nokht͡sol ba olon ulsyn baĭdalHiroki Oka, Batsaĭkhan, Ookhnoĭn Ėmgėnt, Sh Dogmiĭchoĭdon · First published 2006Open the Tome
Mongolyn tu̇u̇kh, ugsaatny sudlalyn zarim asuudaldAi︠u︡udaĭn Ochir, Hiroki Oka · First published 2004Open the Tome
Facets of transformation of the Northeast Asian countriesHiroki Oka · First published 1998Open the Tome