?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Hoang%2C+Van+Xiem&rft.aulast=Hoang&rft.aufirst=Van+Xiem&rft.date=2018&rft.issn=0866-8612&rft.atitle=Cooperative+Caching+in+Two-Layer+Hierarchical+Cache-aided+Systems&rft.title=VNU+Journal+of+Computer+Science+and+Communication+Engineering&rft.genre=article