Analisis yuridis terhadap kasus gugatan wanprestasi perjanjian pengikatan jual beli (PPJB) tanah (Studi kasus putusan Mahkamah Agung Nomor 280 K/PDT/2006) = Juridical analysis Of breach Of contract claims for land preliminary sale and purchase agreement (PPJB tanah - perjanjian pengikatan jual beli tanah) (Case study supreme court decision number 280 K/PDT/2006) - Siahaan, Zefanya, author (Fakultas Hukum Universitas Indonesia, 2012)