Fujiwara no Teika (English Wikipedia)

Nussbaum, Louis-Frédéric. (2005). "Fujiwara Sadaie" in Japan Encyclopedia, p. 208, p. 208, at Google Books
Nussbaum, Louis-Frédéric. (2005). In Japan Encyclopedia at Google Books; Brinkley, Frank et al. (1915).
Brown, Delmer M. and Ichirō Ishida, eds. (1979). Gukanshō: The Future and the Past. Berkeley: University of California Press. ISBN 978-0-520-03460-0; OCLC 251325323

britannica.com

ネケト. 二条家（摂家） (in Japanese). Archived from the original on August 15, 2004. Retrieved September 9, 2007.
ネケト. 一条家（摂家） (in Japanese). Retrieved August 18, 2007.

"The high quality of poetic theory (karon) in this age depends chiefly upon the poetic writings of Fujiwara Shunzei and his son Teika. The other theorists of tanka writing, stimulated by father and son either to agreement or disagreement, contributed also toward the high level of poetic theory, but we may say that Shunzei and Teika were most representative of the age." This quote is sourced to Odagiri Hideo in pg 10 of his "Nihon ni okeru bungei hyōron no seiritsu" (The Rise of Art Criticism in Japan), pub. by Geijutsuron-shū ("Collection of Discussions of Art"), Tokyo 1962; see Shun'ichi H. Takayanagi's review of Japanese Court Poetry by Robert H. Brower and Earl Miner in Monumenta Nipponica, Vol. 18, No. 1/4. (1963), pp. 352–364. [1]
Extract from "Fujiwara Teika's Maigetsusho" by Robert H. Brower, Monumenta Nipponica, Vol. 40, No. 4. (Winter, 1985), pp. 399–425.

Kimoto, Yoshinobu (2004). "『牛屋大臣』藤原是公について" [On "Ushiya-Daijin" Fujiwara no Korekimi]. 奈良時代の藤原氏と諸氏族 [The Fujiwara Clan and Other Clans of the Nara Period] (in Japanese). Ohfu.

"Differences among the earliest of these are not entirely negligible, but readers interested in Kokinshū as it was known to almost everyone who read or cited it after its recanonization in the late 12th century can be advised to begin with one of the 18 or so versions believed to have been transcribed and edited by Fujiwara Teika from 1209 until 1237, four years before his death." From the article "What is Kokin Wakashu?", provided by the University of Virginia Japanese Text Initiative

ネケト. 二条家（摂家） (in Japanese). Archived from the original on August 15, 2004. Retrieved September 9, 2007.

Brinkley, Frank and Dairoku Kikuchi. (1915). A History of the Japanese People from the Earliest Times to the End of the Meiji Era. New York: Encyclopædia Britannica. OCLC 413099
Brown, Delmer M. and Ichirō Ishida, eds. (1979). Gukanshō: The Future and the Past. Berkeley: University of California Press. ISBN 978-0-520-03460-0; OCLC 251325323