diff --git a/nucleons.jl b/nucleons.jl
index d42a52f..2d50817 100644
--- a/nucleons.jl
+++ b/nucleons.jl
@@ -1,4 +1,4 @@
-using DifferentialEquations
+using DifferentialEquations, Interpolations
 include("bisection.jl")
 include("common.jl")
 include("system.jl")
diff --git a/system.jl b/system.jl
index 39d916b..3ccf6cb 100644
--- a/system.jl
+++ b/system.jl
@@ -1,5 +1,3 @@
-using Interpolations
-
 "Tabulates a nucleon spectrum (protons or neutrons) containing κ and occupancy"
 struct spectrum
     κ::Vector{Int}