Factorize each of the following expressions:
(a2)2 – [4 (b – c)2]
= [a2 + 4 (b – c)2] [a2 – 4 (b – c)2]
= [a2 + 4 (b – c)2] [(a + 2b – 2c) (a – 2b + 2c)]