diff --git a/src/intervals/functions.jl b/src/intervals/functions.jl
index 5c38dd4f8..745d05daa 100644
--- a/src/intervals/functions.jl
+++ b/src/intervals/functions.jl
@@ -211,9 +211,12 @@ function pow(x::Interval, n::Integer)  # fast integer power
 
     else
 
-        return Interval(power_by_squaring(x.lo, n, RoundDown),
-                        power_by_squaring(x.hi, n, RoundUp))
+        a = power_by_squaring(x.lo, n, RoundDown)
+        b = power_by_squaring(x.hi, n, RoundUp)
 
+        (a <= b) && return Interval(a, b)
+
+        return Interval(b, a)
     end
 
 end
diff --git a/src/multidim/intervalbox.jl b/src/multidim/intervalbox.jl
index 9cdf8cc67..eedb45ce3 100644
--- a/src/multidim/intervalbox.jl
+++ b/src/multidim/intervalbox.jl
@@ -50,8 +50,8 @@ Return a vector of the `mid` of each interval composing the `IntervalBox`.
 
 See `mid(X::Interval, α=0.5)` for more informations.
 """
-mid(X::IntervalBox) = mid.(X.v)
-mid(X::IntervalBox, α) = mid.(X.v, α)
+mid(X::IntervalBox) = mid.(X)
+mid(X::IntervalBox, α) = mid.(X, α)
 
 big(X::IntervalBox) = big.(X)