The Chinese phrase Four Great Ancient Capitals of China (中国四大古都 pinyin zhong1 guo2 si4 da4 gu3 du1) refers to Nanjing, Beijing, Xi'an, and Luoyang.
... variety of DRM systems have also been employed to restrict access to eBooks[?]. See the TCPA / Pallidium FAQ maintained by Professor Ross J Anderson on his Web site at ...