*[Programming in Oberon](http://www-old.oberon.ethz.ch/WirthPubl/ProgInOberon.pdf)(PDF)
*[Object-Oriented Programming in Oberon-2](http://ssw.jku.at/Research/Books/Oberon2.pdf)(PDF)
*[Programming in Oberon](http://www-old.oberon.ethz.ch/WirthPubl/ProgInOberon.pdf)(PDF)
###Objective-C
*[Programming With Objective-C](https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/ProgrammingWithObjectiveC.pdf)(PDF)
*[Object-Oriented Programming with Objective-C](http://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/OOP_ObjC/OOP_ObjC.pdf)(PDF)
*[Objective-C Succinctly, Syncfusion](http://www.syncfusion.com/resources/techportal/ebooks/objective-c)(PDF, Kindle) *(Just fill the fields with any values)*
*[Programming With Objective-C](https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/ProgrammingWithObjectiveC.pdf)(PDF)