Here are bibliographies related to language democracy:
Home: ccat.sas.upenn.edu/%7Eharoldfs/540/tables/listabl.html
Home: http://www.geocities.com/dspichtinger/Uni/biblio.htm
"Available in print and in several electronic versions, the MLA International Bibliography annually indexes over 66,000 books and articles." (The MLA also includes new books and articles on Esperanto and other planned languages.)
Home: www.mla.org/bibliography
Serĉilo pri literaturo kaj aŭdvidaj dokumentoj ĉe la Internacia Esperanto-Muzeo en Vieno.
Home: allegro.onb.ac.at/cgi-bin/allegro/maske.pl?db=esperanto&lang=esp