أرسل هذا في رسالة قصيرة: Markov switching dynamic correlation: An empirical study of hedging in crude oil and natural gas markets

 __   _      ___     _____       ___     _    _   
| || | ||   / _ \\  |  __ \\    / _ \\  | |  | || 
| '--' ||  | / \ || | |  \ ||  | / \ || | |/\| || 
| .--. ||  | \_/ || | |__/ ||  | \_/ || |  /\  || 
|_|| |_||   \___//  |_____//    \___//  |_// \_|| 
`-`  `-`    `---`    -----`     `---`   `-`   `-`