North American Vexillological Society - www.nava.org/

Flags of Canada - fraser.cc/FlagsCan/index.html

Flags of the World - www.crwflags.com/fotw/flags/

Flagepedia - www.flagpedia.net/

r/vexillology - www.reddit.com/r/vexillology/

r/flags - www.reddit.com/r/flags/

World Flag Database - www.flags.net/