19. 参考
• Using Swift with Cocoa and Objective-C
https://developer.apple.com/library/ios/
documentation/Swift/Conceptual/
BuildingCocoaApps/MixandMatch.html
• Swift and Objective-C Interoperability
https://developer.apple.com/videos/wwdc/
2015/?id=401
• Objective-CプロジェクトにSwift mix してハマったこ
と(随時更新)
http://qiita.com/toshi0383/items/
063205e0d188e9ef6e1d