Analisis terhadap pertimbangan hukum oleh hakim pada perkara No.456/PDT.G/2011/PN.TNG dan No.48/PDT/2012/PT.BTN tentang wanprestasi = Analysis on judges' law consideration on case No.456/PDT.G/2011/PN.TNG and No.48/PDT/2012/PT.BTN for breach of contract - Sanger, Sonya Fransisca (2013)