السورس https://github.com/zekiriabd/Xamarin/blob/master/Xamarin.Auth.Demo.md الاتصال عن طريق الفيس بوك https://developers.facebook.com​ https://satvasolutions.com/difference-between-xamarin-auth-and-xamarin-facebook-native/​ https://www.c-sharpcorner.com/article/oauth-login-authenticating-with-identity-provider-in-xamarin-forms/​ https://www.youtube.com/watch?v=WdpbXpGGjSE​ https://www.youtube.com/watch?v=xGW9Q4atJNc​