Bing found the following results
Otwock - Wikipedia
Otwock - Jewish Virtual Library
History | Virtual Shtetl
Otwock - Holocaust Historical Society
Otwock | Encyclopedia.com
A Guide to the Wooden Villas of Otwock | Article | Culture.pl
Story of the Post-Holocaust Children’s Home in Otwock, Poland
Teacher’s Guide on the Otwock Children’s Home - Yad Vashem.
Remembering Otwock, Poland in the 1930s | Yiddish Book Center
The Map of Otwock Ghetto | Artefact | Montreal Holocaust Museum