To delineate certain small sections of the border more precisely, additional agreements were signed on 24 September 1997 and 4 July 1998. Over the next several years, the border was demarcated on the ground by joint commissions. According to the commissions protocols and maps, the two countries' border line is 1782.75 km long, including 1215.86 km of land border and 566.89 km of border line run along (or across) rivers or lakes. The commissions' work was documented by several joint protocols, finalized with the Protocol signed in Beijing on May 10, 2002. In April 2020, sohu.com a major Chinese internet company published an article "Why Kazakhstan is eager to return to China". The article stated that historically Kazakhstan had been part of China's territory and Kazakhs "do not have too many complaints" about being repeatedly invaded by China. The article raised an alarm in the Kazakhstan government which summoned the Chinese ambassador to lodge a protest over the article. The two most important rivers of eastern Kazakhstan, the Irtysh and the Ili, flow from China. Their waters are extensively used for irrigation and urban water supply in both countries (in particular, via China's Irtysh–Karamay–Ürümqi Canal and Kazakhstan's Irtysh–Karaganda Canal). Besides, the Ili is the main source of water for Kazakhstan's Lake Balkhash, and the smaller Emil River, also flowing from China, supplies water to Kazakhstan's Lake Alakol. Accordingly, since the 1990s, the increasing use of the two transboundary rivers' water in China has been of concern for Kazakhstan's environmentalists and politicians. Bilateral negotiations are periodically conducted on the related issues. Some say Kazakhstan is the most influential Central Asian country and is an important gateway for cultural exchanges between China and Central Asia. Kazakhstan advocates solving global issues via mutual cooperation and relies on supranational organizations to achieve cooperation between civilizations. Kazakhstan is not only a representative of Central Asia, but also the embodiment of Muslim civilization and has influence around the world. Thus China can learn from Kazakhstan and the two from each other mutually. The countries can set up an example of cross-cultural cooperation so that the people of Central Asia and China can better understand each other. Indeed, President Nazarbayev once said that both China and Kazakhstan have a long common history, similar traditions and cultures, and are multi-ethnic countries. Therefore, cultural exchanges between the two countries are very important.