Pengaruh ukuran perusahaan, pertumbuhan penjualan, struktur aset, leverage, degree of operating leverage dan degree of financial leverage terhadap profitabilitas perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia periode 2011-2013 = The effect of size, sales growth, tangibility of assets, leverage degree of operating leverage, and degree of financial leverage to profitability manufacturing companies listed in Indonesia Stock Exchange period 2011-2013