Explanation 28x28 magic square
The 28x28 magic square is an odd multiple of 4. A Franklin panmagic 28x28 square does not exist (a Franklin [not pan]magic square can be constructed with help of the computer).
Methods to construct the 28x28 magic square are:
For the 28x28 magic square I do not show how to composite the 28x28 magic square (see 12x12, 16x16 or 20x20 magic square) or how to use symmetric transformation (see 12x12, 16x16 or 20x20 magic square).
The concentric 28x28 magic square is a 'special'
Basic key method (ultra magic) leads to ultra magic 28x28 squares.
The remaining methods lead to most perfect magic 28x28 squares.