How to Create a Believable Magic System

https://atsiko.wordpress.com/2009/10/29/how-to-create-a-believable-magic-system/amp/?epik=dj0yJnU9TUhqSEg1aVI5bVVDTV9jbU1DajhTWUlEd0ZhMU9vMEkmbj1PSFNxWU52RGROU0xZLWx3SDJNMXp3Jm09MyZ0PUFBQUFBRjFJNXFj