Analisis Pengaruh Perubahan Harga Minyak Terhadap Tingkat Pengembalian Indeks Sektoral Bursa Efek Indonesia Pada Periode Sebelum Krisis (Januari 2006-Desember 2007), Saat Krisis (Januari 2008-Juni 2009) Dan Pasca Krisis Ekonomi 2008 (Juli 2009-Desember 2014) = Analysis of The Impact of Oil Price Change on Indonesia Stock Exchange Sectoral Index Return on Pre-Crisis (January 2006-December 2007), Within the Financial Crisis (January 2008-June 2009), and Post-Crisis 2008 (July 20009-December 2014)