These sites were all instrumental in my research for Tutti’s Promise and may help you or your students with research as well.

Amsterdam and the Netherlands
Amsterdam City Archives
ANP – Historical Archive Community
Delpher Kranten (Dutch newspapers)
Dutch National Archives
Dutch Resistance Museum
Hollandsche Shouwburg (Dutch Theater)
Image Bank WWII
Jewish Historical Museum – Netherlands
Jews Monument
National Archives of the Netherlands
The National Westerbork Memorial
NIOD – Netherlands Institute for War, Holocaust, and Genocide Studies

Genealogy
Ancestry.com
Geni
JewishGen

Germany
International Tracing Service
North Rhein Westfalen Archive

Holocaust and Genocide Information
Anne Frank
EHRI
The Holocaust – Lest We Forget
iWitness
Shoah Foundation

Museum Based Archives
US Holocaust Memorial Museum
Yad Vashem

Terezín and the Czech Republic
Ghetto Museum
Jewish Museum Prague

Theater and Music
Max Ehrlich Association
Westerbork Serenade

US Military
Military History Online