Analisis yuridis persekongkolan tender dalam pengadaan bus Transjakarta (medium bus, single bus, dan articulated bus) tahun anggaran 2013 : studi kasus Putusan KPPU Nomor 15/KPPU-I/2014 = Juridical analysis of tender collusion in Transjakarta's buses procurement (medium bus, single bus, and articulated bus) fiscal year 2013 : case study KPPU's decision Number 15/KPPU-I/2014