OPAC (Online Public Access Catalogue) of University Town Library of Shenzhen
深圳大学城图书馆馆藏目录查询系统
OPAC of Peking University Library
北京大学图书馆馆藏目录查询系统
WorldCat (Turn on PKU-VPN access)
WorldCat is a union catalog of thousands of libraries around the world. It is probably the most comprehensive library catalog in the world.
WorldCat 是一个由全球数千家图书馆联合编制的馆藏目录，也是世界上最全面的图书馆目录。
The Library of Congress located in Washington, DC is one of the largest libraries in the world and its catalog contains millions of records of books and journals.
位于美国华盛顿特区的国会图书馆是世界上最大的图书馆之一，其馆藏目录包含数百万条书籍和期刊的记录。