约 445,000 个结果
Serfdom - Wikipedia
History of serfdom - Wikipedia
Serfdom | History & Examples | Britannica
Serfdom: Eastern Europe - Encyclopedia.com
serfdom summary | Britannica
Serfdom - New World Encyclopedia
Serf - World History Encyclopedia
Serfdom: Western Europe - Encyclopedia.com
Khan Academy
Serfdom - Encyclopedia.com