Update

twos_complement.md

@@ -10,7 +10,7 @@ Why is two's complement so great? Its most notable advantages are:
 - **Positive values and zero are the same as the straightforward unsigned representation**, i.e. it is "backwards compatible" with the straightforward representation. For example the 4 bit value `0011` represents number 3 in two's complement just like it does in a normal unsigned binary number. (This also holds in sign-magnitude and one's complement.)
 - **Multiplying by -1 is still relatively simple** -- even though it is a tiny bit more expensive than in one's complement or sign-magnitude, it is still pretty straightforward (only requires two operations instead of one) and in [hardware](hardware.md) it can be implemented just as fast.
 
-TODO: disadvantages?
+TODO: disadvantages? Sign extensions maybe.
 
 *N* bit number in two's complement can represent numbers from *-(2^N) / 2* to *2^N / 2 - 1* (including both). For example with 8 bits we can represent numbers from -128 to 127.
 
@@ -32,3 +32,8 @@ The following is a comparison of the different representations, notice the shini
 |  101  | 5        | -3         | -1        | -2         | 1      |
 |  110  | 6        | -2         | -2        | -1         | 2      |
 |  111  | 7        | -1         | -3        | -0         | 3      |
+
+## See Also
+
+- [posit](posit.md)
+- [conum](conum.md)