Collections of Chinese art and Asian export art at Peabody-Essex Museum, Salem, MA: www.pem.org.
Chinese House at Peabody-Essex Museum, Salem, MA: www.pem.org/yinyutang/.
Maine Memory Network: www.mainememory.net. Go to Exhibits to see a presentation on Chinese in Maine.
Washington State University Course Notes Online: Ch’ing China Link.
Making a Chinese Compass: Link.
There are a number of other resources on the web that provide statistics and history on China, such as the China Internet Information Center at: www.china.org.cn and China Today, at: www.chinatoday.com.
History of the Abacus and its use: Link.