Revert "Remove Wikipedia links"

This reverts commit b18c2a2.

Author: xanni

exercises/square-root/instructions.md

@@ -11,3 +11,8 @@ Some potential approaches:
 - Linear or binary search for a number that gives the input number when squared.
 - Successive approximation using Newton's or Heron's method.
 - Calculating one digit at a time or one bit at a time.
+
+You can check out the Wikipedia pages on [integer square root][integer-square-root] and [methods of computing square roots][computing-square-roots] to help with choosing a method of calculation.
+
+[integer-square-root]: https://en.wikipedia.org/wiki/Integer_square_root
+[computing-square-roots]: https://en.wikipedia.org/wiki/Methods_of_computing_square_roots