Madhavan, Jayant; Ko, David; Kot, Lucja; Ganapathy, Vignesh; Rasmussen, Alex & Havely, Alon. «Google’s DeepWeb Crawl»(en inglés). Consultado el 30 de octubre de 2014.
Grossman, Lev (11 de noviembre de 2013). «The Deep Web.». Time(en inglés). Consultado el 28 de octubre de 2014. «Technically the Deep Web refers to the collection of all the websites and databases that search engines like Google don't or can't índex».
Iffat, Rabia (1 de octubre de 2010). «Understanding the Deep Web». Library Philosophy and Practice 2010(en inglés). Consultado el 28 de octubre de 2014. «Surface Web is made up of static and fixed pages, whereas Deep Web is made up of dynamic pages. Static pages do not depend on a database for their content. They reside on a server waiting to be retrieved, and are basically html files whose content never changes.»
Iffat, Rabia (1 de octubre de 2010). «Understanding the Deep Web». Library Philosophy and Practice 2010(en inglés). Consultado el 28 de octubre de 2014. «Public information on the Deep Web is currently 400-550 times larger than the commonly-defined World Wide Web. The Deep Web contains 7,500 terabytes of information, compared to 19 on the Surface Web. Deep Web contains nearly 550 billion individual documents compared to one billion on the Surface Web. More than 200,000 Deep Web sites presently exist.»
He, Bin (1 de mayo de 2007). «Ebscohost.». Communications of the ACM(en inglés). Consultado el 29 de octubre de 2014. «Google and Yahoo both indexed 32% of the deep Web objects, and MSN had the smallest coverage of 11%. However, there was significant overlap in what they covered: the combined coverage of the three largest search engines increased only to 37%, indicating they were indexing almost the same objects.»
Iffat, Rabia (1 de octubre de 2010). «Understanding the Deep Web». Library Philosophy and Practice 2010(en inglés). Consultado el 28 de octubre de 2014. «The content of the Deep Web is rarely shown in a search engine result, since the search engine spiders do not crawl into databases and extract the data. These spiders can neither think nor type, but jump from link to link. As such, a spider cannot enter pages that are password protected. Web page creators who do not want their page shown in search results can insert special meta tags to keep the page from being indexed. Spiders are also unable to pages created without the use of html, and also links that include a question mark. But now parts of the Deep Web with non-html pages and databases with a question mark in a stable URL are being indexed by search engines, with non-html pages converted to html. Still, it is estimated that even the best search engines can access only 16 percent of information available on the Web. There are other Web search techniques and technologies that can be used to access databases and extract the content.»
Grossman, Lev (11 de noviembre de 2013). «The Deep Web.». Time(en inglés). Consultado el 28 de octubre de 2014. «Unlike conventional Internet browsers, Tor's allows users to surf the Web anonymously. Tor is downloaded 30 million-50 million times a year. There are 800,000 daily Tor users―a jump of 20% in the past year. Tor can access 6,500 hidden websites.»
Grossman, Lev (11 de noviembre de 2013). «The Deep Web.». Time(en inglés). Consultado el 28 de octubre de 2014. «Bitcoin».
Raghavan, Sriram; Garcia-Molina, Hector (11-14 de septiembre de 2001). «Crawling the Hidden Web». 27th International Conference on Very Large Data Bases (Roma, Italia).
