Here are examples of each type of historical data source. You can imagine that there are many other of the same types in different cities, states, regional areas...even countries!
Open Educational Resources or OERs give students access to books, maps and other materials that are free to use. Always check the terms under which sources are allowed to be used since individual sources could have restrictions.
Note that citation style used will depend on class and/or subject matter of map
Private Images 
Do not use without permission
Public Images
