Interlinguistics of interlinguistics are, however, not so constructive, but rather descriptive, comparative, historic, sociolinguistic, or concerned with translation by humans or machines. As for Esperanto, which is the most widely used constructed interlanguage, there is a relatively abundant literature about the language itself and its philology (see Esperantology). Only a few of the many constructed languages have been applied practically to any noteworthy extent. The most prosperous were Volapük (1879, Johann Martin Schleyer), Esperanto (1887 Ludwik Lejzer Zamenhof), Latino sine flexione (1903, Giuseppe Peano), Ido (1907, Louis Couturat), Occidental-Interlingue (1922, Edgar de Wahl) and Interlingua (1951, IALA and Alexander Gode), with
Ludwik Kowalski on Physics, a textbook on Physics, and two books on Stalinism. In January 2011, Hoover Institution archived his original notebook diaries (in Polish), letters, and personal documents and photographs. His papers can be found online. His presentations can be found online. One of his memoirs is an autobiography based on a diary he kept between 1946 and 2004 (in the USSR, Poland, France, and the USA) and illustrates his evolution from one extreme to another—from devoted Stalinist to active anti-communist: Ludwik Kowalski Ludwik Kowalski (born 1931) is a Polish-American physicist, anti-communist author, and professor emeritus of Montclair State University in