diff --git a/Project.toml b/Project.toml
index 91e242d6..3e6d0030 100644
--- a/Project.toml
+++ b/Project.toml
@@ -6,12 +6,22 @@ version = "0.1.6"
 [deps]
 CommonSolve = "38540f10-b2f7-11e9-35d8-d573e4eb0ff2"
 IntervalArithmetic = "d1acc4aa-44c8-5952-acd4-ba5d80a2a253"
+IntervalConstraintProgramming = "138f1668-1576-5ad7-91b9-7425abbf3153"
+LazySets = "b4f0291d-fe17-52bc-9479-3d1a343d9043"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 OpenBLASConsistentFPCSR_jll = "6cdc7f73-28fd-5e50-80fb-958a8875b1af"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 
+[extensions]
+IntervalConstraintProgrammingExt = "IntervalConstraintProgramming"
+LazySetsExt = "LazySets"
+
+[weakdeps]
+IntervalConstraintProgramming = "138f1668-1576-5ad7-91b9-7425abbf3153"
+LazySets = "b4f0291d-fe17-52bc-9479-3d1a343d9043"
+
 [compat]
 CommonSolve = "0.2"
 IntervalArithmetic = "0.20.5"
diff --git a/src/linear_systems/oettli_nonlinear.jl b/ext/IntervalConstraintProgrammingExt.jl
similarity index 74%
rename from src/linear_systems/oettli_nonlinear.jl
rename to ext/IntervalConstraintProgrammingExt.jl
index 0548f349..d0592d54 100644
--- a/src/linear_systems/oettli_nonlinear.jl
+++ b/ext/IntervalConstraintProgrammingExt.jl
@@ -1,4 +1,12 @@
-using .IntervalConstraintProgramming
+module IntervalConstraintProgrammingExt
+
+if !isdefined(Base, :get_extension)
+    using ..IntervalLinearAlgebra
+    using ..IntervalConstraintProgramming
+else
+    using IntervalLinearAlgebra
+    using IntervalConstraintProgramming
+end
 
 """
 returns the unrolled expression for \$|a ⋅x - b|\$
@@ -44,18 +52,17 @@ function oettli_eq(a, b, x)
     rhs = oettli_rhs(ar, br, x)
     ex = :(@constraint $lhs - $rhs <= 0)
     @eval $ex
-
 end
 
-
-
-function (op::NonLinearOettliPrager)(A, b, X::IntervalBox)
+function (op::IntervalLinearAlgebra.NonLinearOettliPrager)(A, b, X::IntervalBox)
     vars = ntuple(i -> Symbol(:x, i), length(b))
     separators = [oettli_eq(A[i,:], b[i], vars) for i in 1:length(b)]
     S = reduce(∩, separators)
     return Base.invokelatest(pave, S, X, op.tol)
 end
 
-(op::NonLinearOettliPrager)(A, b, X=enclose(A, b)) = op(A, b, IntervalBox(X))
+(op::IntervalLinearAlgebra.NonLinearOettliPrager)(A, b, X=enclose(A, b)) = op(A, b, IntervalBox(X))
+
+IntervalLinearAlgebra._default_precondition(_, ::NonLinearOettliPrager) = NoPrecondition()
 
-_default_precondition(_, ::NonLinearOettliPrager) = NoPrecondition()
+end
diff --git a/src/linear_systems/oettli_linear.jl b/ext/LazySetsExt.jl
similarity index 60%
rename from src/linear_systems/oettli_linear.jl
rename to ext/LazySetsExt.jl
index 3c8c5005..ec93c791 100644
--- a/src/linear_systems/oettli_linear.jl
+++ b/ext/LazySetsExt.jl
@@ -1,6 +1,14 @@
-using .LazySets
+module LazySetsExt
 
-function (opl::LinearOettliPrager)(A, b)
+if !isdefined(Base, :get_extension)
+    using ..IntervalLinearAlgebra
+    using ..LazySets
+else
+    using IntervalLinearAlgebra
+    using LazySets
+end
+
+function (opl::IntervalLinearAlgebra.LinearOettliPrager)(A, b)
     n = length(b)
     Ac = mid.(A)
     bc = mid.(b)
@@ -22,4 +30,6 @@ function (opl::LinearOettliPrager)(A, b)
     return identity.(filter!(!isempty, polytopes))
 end
 
-_default_precondition(_, ::LinearOettliPrager) = NoPrecondition()
+IntervalLinearAlgebra._default_precondition(_, ::LinearOettliPrager) = NoPrecondition()
+
+end
diff --git a/src/IntervalLinearAlgebra.jl b/src/IntervalLinearAlgebra.jl
index 975af56d..db7f9576 100644
--- a/src/IntervalLinearAlgebra.jl
+++ b/src/IntervalLinearAlgebra.jl
@@ -1,8 +1,12 @@
 module IntervalLinearAlgebra
 
-using StaticArrays, Requires, Reexport
+using StaticArrays, Reexport
 using LinearAlgebra: checksquare
 
+if !isdefined(Base, :get_extension)
+    using Requires
+end
+
 import Base: +, -, *, /, \, ==,
             show, convert, promote_rule, zero, one,
             getindex, IndexStyle, setindex!, size
@@ -54,20 +58,23 @@ else
 end
 
 function  __init__()
-    @require IntervalConstraintProgramming = "138f1668-1576-5ad7-91b9-7425abbf3153" include("linear_systems/oettli_nonlinear.jl")
-    @require LazySets = "b4f0291d-fe17-52bc-9479-3d1a343d9043" include("linear_systems/oettli_linear.jl")
+    @static if !isdefined(Base, :get_extension)
+        @require IntervalConstraintProgramming = "138f1668-1576-5ad7-91b9-7425abbf3153" include("../ext/IntervalConstraintProgrammingExt.jl")
+        @require LazySets = "b4f0291d-fe17-52bc-9479-3d1a343d9043" include("../ext/LazySetsExt.jl")
+    end
+
     if Sys.ARCH == :x86_64
         @info "Switching to OpenBLAS with ConsistentFPCSR = 1 flag enabled, guarantees
         correct floating point rounding mode over all threads."
         BLAS.lbt_forward(OpenBLASConsistentFPCSR_jll.libopenblas_path; verbose =  true)
-        
+
         N = BLAS.get_num_threads()
         K = 1024
         if NumericalTest.rounding_test(N, K)
             @info "OpenBLAS is giving correct rounding on a ($K,$K) test matrix on $N threads"
         else
             @warn "OpenBLAS is not rounding correctly on the test matrix"
-            @warn "The number of BLAS threads was set to 1 to ensure rounding mode is consistent"    
+            @warn "The number of BLAS threads was set to 1 to ensure rounding mode is consistent"
             if !NumericalTest.rounding_test(1, K)
                 @warn "The rounding test failed on 1 thread"
             end