List of useful links for musicologists, and musicians in general, focusing mainly on early music and Czech resources.
Digital Resources for Musicology - https://drm.ccarh.org/
Golden Pages for Musicologists - https://goldenpages.miraheze.org/wiki/Main_Page
Online Resources for Music Scholars - https://guides.library.harvard.edu/onmusic
List of online digital musical document libraries - https://en.wikipedia.org/wiki/List_of_online_digital_musical_document_libraries
Music in MusicXML Format - https://www.musicxml.com/music-in-musicxml/
Encyklopedias, dictionaries
Grove Music Online - https://www.oxfordmusiconline.com/grovemusic/
Die Musik in Geschichte und Gegenwart - https://www.mgg-online.com/
Český hudební slovník - https://www.ceskyhudebnislovnik.cz/
Literature
The Union Catalogue of the Czech Republic - https://aleph.nkp.cz/F/?func=file&file_name=find-b&local_base=skc&CON_LNG=ENG
Musica Subject Gateway - https://mus.knihovny.cz/?lng=en
WorldCat - https://www.worldcat.org/
Discovery Service UKAŽ (Charles University) - https://ukaz.cuni.cz/en
Sheet music
Electronic and Virtual Editions - https://eve.ccarh.org/
International Music Score Library Project - https://imslp.org/
Choral Public Domain Library - https://www.cpdl.org/
GregoBase - https://gregobase.selapa.net/
Web Library of Seventeenth-Century Music - https://www.sscm-wlscm.org/
Musikedition Tirol - https://musikedition.musikland-tirol.at/
Gesualdo Online - https://ricercar.gesualdo-online.cesr.univ-tours.fr/
Measuring Polyphony - https://measuringpolyphony.org/
Marenzio Online Digital Edition - http://www.marenzio.org/
New Senfl Edition - https://senflonline-eng.com/
Monte-Online-Project - http://monte-online.org/
Primary sources
RISM Resources - https://opac.rism.info/index.php?id=9
Europeana - https://www.europeana.eu/
Internet Archive - https://archive.org/
Google Books - https://books.google.com/
Google Scholar - https://scholar.google.com/
databases
RISM Online - https://rism.online/
RISM Library Sigla - https://rism.info/community/sigla.html
DIAMM - https://www.diamm.ac.uk/
Cantus Index - http://cantusindex.org/
Gregorien - https://gregorien.info/en
Medieval Music Manuscripts Online Database - http://musmed.eu/
The Mass Database - http://www.mdb.uni-mainz.de/
The Polyphony Database - https://www.polyphonydatabase.com/
Motet Cycles Database - http://motetcycles.ch/
Printed Sacred Music Database - http://www.printed-sacred-music.org/
A Catalogue of Motets, Mass, Office, and Holy Week Music Printed in Italy, 1516–1770 - https://sscm-jscm.org/instrumenta/instrumenta-volumes/instrumenta-volume-2/
by country
https://en.wikipedia.org/wiki/Category:Digital_libraries_by_country
Czechia
Digital Library of the National Library (Prague) - https://ndk.cz/
Digital Library of the Moravian Library (Brno) - https://www.digitalniknihovna.cz/mzk
Manuscriptorium - https://www.manuscriptorium.com/cs
Prague City Archives - http://dokumenty.ahmp.cz/dokumenty/
Czech Museum of Music - https://cmh.opac.nm.cz/
Melodiarium hymnologicum Bohemiae - https://melodiarium.musicologica.cz/
LIMVP - http://www.clavmon.cz/limup/
Slovakia
Digital library of the Slovak National Library - https://dikda.snk.sk/
Univerzitná knižnica v Bratislave - http://digitalna.kniznica.info/
Slovak Early Music Database - http://cantus.sk/
Germany
Deutsche Digitale Bibliothek - https://www.deutsche-digitale-bibliothek.de/
Austria
Österreichische Nationalbibliothek - https://onb.digital/
Mittelalterliche Handschriften in Österreich - https://manuscripta.at/
Landesbibliotheken Österreichs - https://landesbibliotheken.at/
VerbundServer der Theologischen und Kirchlichen Institutionen - https://vthk.eu/
Poland
Federacja Bibliotek Cyfrowych - https://fbc.pionier.net.pl/
Polona (Biblioteka Narodowa) - https://polona.pl/
Jagiellońska Biblioteka Cyfrowa - https://jbc.bj.uj.edu.pl/
Cyfrowa Biblioteka Diecezjalna w Sandomierzu - https://bc.bdsandomierz.pl/
Śląska Biblioteka Cyfrowa - https://www.sbc.org.pl/
Hungary
Digital Archives Portal - https://www.eleveltar.hu/
Italy
Servizio Bibliotecario Nazionale - https://opac.sbn.it/
Museo internazionale e biblioteca della musica di Bologna - http://www.bibliotecamusica.it/
The Sound of St Mark's (Venetian Music Online) - http://vmo.unive.it/choirbooks/
Vatican City
Biblioteca Apostolica Vaticana - https://digi.vatlib.it/mss
Spain
Biblioteca Digital Hispánica - http://bdh.bne.es/
Spanish Early Music Manuscripts Database - http://musicahispanica.eu/
Inventari dels Fons Musicals de Catalunya - https://ifmuc.uab.cat/
Libros de polifonía hispana - https://hispanicpolyphony.eu/home
Memòria Digital de Catalunya - http://mdc1.csuc.cat
Fons Musical de la Catedral de Barcelona - https://mdc.csuc.cat/digital/collection/musicatedra
La Biblioteca Virtual del Patrimonio Bibliográfico - https://bvpb.mcu.es/musica/es/micrositios/inicio.do
Real Biblioteca del Monasterio de San Lorenzo de El Escorial - https://rbmecat.patrimonionacional.es/
Portugal
Biblioteca Nacional Digital - https://bndigital.bnportugal.gov.pt/
The Portuguese Early Music Database - http://pemdatabase.eu/
France
Gallica - https://gallica.bnf.fr/
Great Britain
British Library - https://explore.bl.uk/
Switzerland
e-codices - http://www.e-codices.unifr.ch/
Sweden
The Düben Collection Database Catalogue - https://www2.musik.uu.se/duben/Duben.php
Belgium
Koninklijke Bibliotheek van België - https://belgica.kbr.be/
United States of America
Library of Congress - https://www.loc.gov/notated-music/
Biblioteca Digital del Patrimonio Iberoamericano - http://www.iberoamericadigital.net/
Muzikological and musical institutions
Czechia
Department of Musicology, Czech Academy of Sciences - https://www.udu.cas.cz/cz/oddeleni/muzikologie
Slovakia
Institute of Musicology, Slovak Academy of Sciences - http://uhv.sav.sk/en/
educational
Institute of Musicology, Faculty of Arts, Charles University (Prague) - https://uhv.ff.cuni.cz/en/
Department of Musicology, Faculty of Arts, Palacky University (Olomouc) - https://muzikologie.upol.cz/en/
Department of Musicology, Faculty of Arts, Masaryk University (Brno) - https://www.phil.muni.cz/en/about-us/organisational-structure/213400-deptof-musicology
museums, libraries, and archives
Czech Museum of Music - https://www.nm.cz/en/visit-us/buildings/czech-museum-of-music
Music department, National Library of the Czech Republic - https://www.en.nkp.cz/about-us/professional-activities/music
Music department, Municipal Library of Prague - https://www.mlp.cz/en/
Sheet music archive, Czech Radio - https://www.czech.radio/czech-radio-hire-library-8033757
Antonín Dvořák Memorial - https://antonindvorak.cz/en/
Antonín Dvořák Museum - https://www.nm.cz/en/visit-us/buildings/antonin-dvorak-museum
Bedřich Smetana Museum - https://www.nm.cz/en/visit-us/buildings/bedrich-smetana-museum
Leoš Janáček Memorial - https://www.leosjanacek.eu/en/
Jaroslav Ježek Memorial (The Blue Room) - https://www.nm.cz/en/visit-us/buildings/jaroslav-jezek-memorial-the-blue-room
Popmuzeum - Museum and Archive of Popular Music - https://www.popmuseum.cz/
under construction
societies, institutes, foundations
Czechia
Czech musicological society - https://www.cshv.cz/index.php/about-cshv
Society for Early Music - http://ssh.early-music.cz/
Society of Spiritual Music - http://sdh.cz/?a=&j=2
Czech Music Fund - https://www.nchf.cz/en/
Česká společnost pro hudební fyziologii a medicínu hudebníků - https://www.medicinahudebniku.cz/
Society for Electroacoustic Music - http://www.seah.cz/
Společnost pro hudební výchovu ČR - https://www.shvcr.cz/
Hudební informační středisko - https://www.musica.cz/en/
Institut Bohuslava Martinů - https://www.martinu.cz/en/
Karpálová Society - http://www.kapralova.org/
Mozart Society in Czech Republic - https://www.mozartovaobec.cz/?stranka=109
The Czech Handel Society - http://www.haendel.cz/estart.php
Association for Central European Cultural Studies - https://www.acecs.cz/
world
International Musicological Society - https://www.musicology.org/
International Association of Music Libraries, Archives and Documentation Centres - https://www.iaml.info/
European Music Council - https://www.emc-imc.org/
Society for Music Theory - https://societymusictheory.org/
Society for Ethnomusicology - https://www.ethnomusicology.org/
International Council for Traditions of Music and Dance - http://www.ictmusic.org/
European Early Music Network - http://rema-eemn.net/
International Association of Sound and Audiovisual Archives - https://www.iasa-web.org/
International Association of Music Centres - http://www.iamic.net/
European Seminar in Ethnomusicology - http://esem-music.eu/
Welcome to The International Society for Orthodox Church Music - http://www.isocm.com/
Musicological journals in Czechia
under construction
Summer schools of early music in Czechia
Inernational Summer School of Early Music (Valtice) - https://www.early-music.cz/en/
Summer School of Baroque Music (Holešov) - https://www.baroknihudba.cz/en/
under construction
Festivals of early music in Czechia
under construction
Digital humanities
Czechia
Digital Humanities, AV ČR - https://digitalhumanities.cz/en/
Czech Association for Digital Humanities - https://www.czadh.cz/en/
world
Archive of Digital Applications in Musicology - https://wiki.ccarh.org/wiki/Archive_of_Digital_Applications_in_Musicology_(ADAM)
European Association for Digital Humanities - https://eadh.org/
Musical Geography Project - https://musicalgeography.org/
Current musicological projects in Czechia
Old Myths, New Facts - https://www.smnf.cz/en/
Musica Rudolphina - http://www.bibemus.org/musicarudolphina/
Genome of Melody - https://ces-transformationfund.org/our-projects/genome-of-melody/