Eggermont, Pierre Herman Leonard
The chronology of the reign of Asoka Moriya : a comparison of the data of the Asoka inscriptions and the data of the tradition
E.J. Brill, 1956
 Buku Teks
Thapar, B.K.
Recent archaeological discoveries in India / B.K. Thapar
Unesco, 1985
 Buku Teks
Goodman, Craufurd D.
Decline and Renewal
Institute of International Education, 1966
 Buku Teks
Spengler, Oswald
Decline of the west
George Allen and Unwin, 1956
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Neighborhood decline
Ronald Van Kempen; Gideon Bolt; Maarten Van Ham, editors
Routledge, Taylor & Francis Group, 2018
 Buku Teks