There are no restrictions for non residents to buy real estate. I specialize in the San Fernando Valley and I will be happy to answer your questions. Please contact me if I can be of help.
No there are no restrictions if you are not a resident of the USA. In fact, in the past couple of years I have represented non-US residents from Germany (who bought a property in Westlake Village sight unseen!) as well as France and Canada.
I am not sure if you are asking about a specific home or are just making a general enquiry but I cover the area between West Hills and Calabasas to Camarillo, including Oak Park, Agoura Hills, Westlake Village and Thousand Oaks and would be delighted to help you. Feel free to check out my site at http://www.simandmark.com.
I'm not sure exactly which property you are interested in as it was not linked to your question - in general, there are no restrictions on non residents or non citizens of the US purchasing property. Are you just curious or are you interested in possibly purchasing something yourself? If I can answer any other questions for you, please feel free to email me at email@example.com