The OldMapsOnline provides a widget for partners to allow quick access to the OldMapsOnline application. The "similar maps" widget is simple code that is embeddable on other websites which creates a pretty button on the right side of page.
All you need is to add the following code into your web page which has the OldMapsOnline map identification ID:OldMapsOnline
You can modify the style of widget with CSS. See example on jsfiddle.
The OldMapsOnline provides a se of queries which can be usable for quick access to areas:
Latitude and longitude query:
The variables date_from and date_to can be also used in query.
Here are various version of the project logo, the design manual, and badges and banners for the project OldMapsOnline.