Doubled order (n even)

There are several methods, which can double the size of an existing magic square. With small changes, basic magic squares of odd and even order can be processed by these methods.

Method
Benson - Jacoby
Bouteloup
Candy
Chen Zhong-mu
Cram
Hendricks
Medjig
Strachey (Benson-Jacoby Variant)
Widdis - Richter