Pengaruh Risiko Kredit, Risiko Pasar, Risiko Operasional, serta Risiko Likuiditas terhadap Imbal Hasil Saham Perbankan di Indonesia: Studi terhadap Perbankan yang Terdaftar di Bursa Efek Indonesia tahun 2007-2011 = The Influence of Credit Risk, Market Risk, Operational Risk, and Liquidity Risk against Return in Indonesian Banking Stocks: Study on Banks Listed on the Indonesia Stock Exchange during 2007-2011