diff --git a/src/Approximations/overapproximate.jl b/src/Approximations/overapproximate.jl
index bde436f149..81c3ae2074 100644
--- a/src/Approximations/overapproximate.jl
+++ b/src/Approximations/overapproximate.jl
@@ -1318,7 +1318,7 @@ function overapproximate(cap::Intersection{N,
 end
 
 """
-    overapproximate(Z::Zonotope{N}, ::Type{<:Zonotope}, r::Union{Int, Rational{Int}}) where {N<:Real}
+    overapproximate(Z::Zonotope{N}, ::Type{<:Zonotope}, r::Union{Integer, Rational}) where {N<:Real}
 
 Reduce the order of a zonotope by overapproximating with a zonotope with less
 generators.
@@ -1340,7 +1340,7 @@ This function implements the algorithm described in A. Girard's
 
 If the desired order is smaller than one, the zonotope is *not* reduced.
 """
-function overapproximate(Z::Zonotope{N}, ::Type{<:Zonotope}, r::Union{Int, Rational{Int}}) where {N<:Real}
+function overapproximate(Z::Zonotope{N}, ::Type{<:Zonotope}, r::Union{Integer, Rational}) where {N<:Real}
     c, G = Z.center, Z.generators
     d, p = dim(Z), ngens(Z)
 
diff --git a/src/Sets/Zonotope.jl b/src/Sets/Zonotope.jl
index 0d912d2dfb..7e7c60a035 100644
--- a/src/Sets/Zonotope.jl
+++ b/src/Sets/Zonotope.jl
@@ -257,7 +257,7 @@ function scale(α::Real, Z::Zonotope)
 end
 
 """
-    reduce_order(Z::Zonotope, r::Union{Int, Rational{Int}})::Zonotope
+    reduce_order(Z::Zonotope, r::Union{Integer, Rational})::Zonotope
 
 Reduce the order of a zonotope by overapproximating with a zonotope with less
 generators.
@@ -273,9 +273,9 @@ A new zonotope with less generators, if possible.
 
 ### Algorithm
 
-See `overapproximate(Z::Zonotope{N}, ::Type{<:Zonotope}, r::Union{Int, Rational{Int}}) where {N<:Real}` for details.
+See `overapproximate(Z::Zonotope{N}, ::Type{<:Zonotope}, r::Union{Integer, Rational}) where {N<:Real}` for details.
 """
-function reduce_order(Z::Zonotope{N}, r::Union{Int, Rational{Int}})::Zonotope{N} where {N<:Real}
+function reduce_order(Z::Zonotope{N}, r::Union{Integer, Rational})::Zonotope{N} where {N<:Real}
     return overapproximate(Z, Zonotope, r)
 end