Factorize each of the following algebraic expression:

$a^{2}+4 b^{2}-4 a b-4 c^{2}$

$=\left(a^{2}-4 a b+4 b^{2}\right)-4 c^{2}$

$=\left[a^{2}-2 \times a \times 2 b+(2 b)^{2}\right]-4 c^{2}$

$=(a-2 b)^{2}-(2 c)^{2}$

$=[(a-2 b)-2 c][(a-2 b)+2 c]$

$=(a-2 b-2 c)(a-2 b+2 c)$