Sproget: multi-dictionary with meanings in danish: Den Danske Ordbog,
Retskrivningsordbogen
Retskrivningsordbogen: spelling of Danish words
Ordbog over det danske sprog (1700-1950) meanings in Danish
Nye ord i dansk: Danish dictionary of new terms (from 1955 to today)
Danish-English dictionary (multilingual) Swedish, German, French, italian, Spanish, Portuguese
Danish-English dictionary basic, with phonetic
online translation: Danish-English & other languages & web page
useful expressions Danish-English with sound (Loecsen)
useful expressions Danish-English with sound
Dansk ordbog: Danish dictionary by Christian Molbech (1833)
Dansk etymologisk ordbog: Danish etymological dictionary, by Edwin
Jessen (1893)
Dansk synonymik: Danish synonyms, by Peter Erasmus Müller (1872)
Engelsk-Dansk ordbog: Danish-English dictionary by Svend Rosing (1887)
Dictionary of the English and Danish languages, adapted
to the use of schools and learners of both languages, by Cecil Hornbeck (1863)
Danish > English
Dansk-Engelske ordbog: Danish-English dictionary by William
Mariboe (1861)
Dansk-norsk–engelsk ordbog, Dictionary of the
Dano-Norwegian and English languages, by Anton Larsen (1897)
Dansk-norsk–svensk ordbok: Danish-Norwegian–Swedish dictionary by Ida
Natanael Beckman (1907)
Svensk–dansk-norsk ordbog: Swedish–Danish-Norwegian dictionary by Ida
Falbe-Hansen (1912)
Dictionnaire français-danois: French-Danish dictionary
by Lauritz Stephan Borring (1841)
Ordbog til det ældre danske sprog (1300-1700) by Otto Kalkar (1907) 
Danish keyboard to type the special characters of the Danish alphabet
Danish grammar & pronunciation
verb conjugation & Danish-English translation
Teach yourself Danish (2004)
Colloquial Danish: course
for beginners (2003) 
Danish, guide to the spoken language, United States War Department
(1943)
Practical and easy method of learning the Danish and Norwegian languages
by H. Lund (1900)
Danish and Dano-Norwegian grammar by Peter Groth (1894)
Simplified grammar of the Danish language by Elise Otté (1883) &
Swedish
The Danish speaker, pronunciation of the Danish
language, vocabulary, dialogues, and idioms, for the use of students and travellers in Denmark and Norway, by Maria Bojesen (1865)
Guide to the Danish language for English students,
by Maria Bojesen (1863) with phrases translated in English
Danish grammar by Rasmus Rask (1846)
Dansk grammatik: Danish grammar by Edwin Jessen (1891)
books about Danish language: Google
books & Internet archive
Royal Library of Denmark
Danish literature: online books, by authors
- titles - periods
old books: 15th-16th century
books about Danish literature: Google
books & Internet archive
the Bible in Danish
bilingual Bible Danish-English & other languages
Alle mennesker er født frie og lige i værdighed og rettigheder.
De er udstyret med fornuft og samvittighed, og de bør handle mod hverandre i en broderskabets ånd.
First article in many languages
Declaration of Human Rights: bilingual text in Danish, English, Norwegian, Swedish...
Denmark: maps, symbols, heritage & documents
Norwegian - Icelandic - Swedish
Germanic languages (in French)