How to get the iphone address book for a specific phone number using objective c ?

APAddressBook *addressBook = [[APAddressBook alloc] init];
// don't forget to show some activity
[addressBook loadContacts:^(NSArray *contacts, NSError *error)
{
    // hide activity
    if (!error)
    {
        // do something with contacts array
    }
    else
    {
        // show error
    }
}];