Useful Links
http://www.antique-horology.org
Elgin Watch Serial Numbers (http://elginwatches.org/help/serial_number_info.html)
Elgin Watch Serial Numbers - another site (http://trusted-forwarder.org/elgin/databases/elgin_sn_intro.html)
Watch Serial Numbers (http://www.antiquewatchworld.com/watch/html/serials.html)
More Watch Serial Numbers (http://www.watchpolishing.com/watchguide.htm)
More Watch Serial Numbers (http://www.thewatchguy.com/index.html)
More Watch Serial Numbers (http://www.pocketwatchrepair.com/histories/watch-companies.html)
Hamilton Watch Serial Numbers (http://www.antique-pocket-watch.com/hamilton-pocket-watch-serial.html)
Hamilton Watch Serial Numbers (http://www.oldwatch.com/Hamiltondate.html)
Hamilton Watch Serial Numbers (http://www.antiquevintagewatches.com/dates.html)
Illinois Watch Serial Numbers (http://www.pocketwatchsite.com/illinoisserials.html)
Omega Watch Serial Numbers (http://chronomaddox.com/omega_serial_numbers.html)
NAWCC Waltham Serial Number DB (http://www.nawcc-info.org/WalthamDB/walsernum.htm)
Rolex Watch Serial Numbers (http://www.watchbasics.com/rolex_serial_number.htm)