diff --git a/Project.toml b/Project.toml
index 25a2310..10c18da 100644
--- a/Project.toml
+++ b/Project.toml
@@ -13,6 +13,9 @@ SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 AbstractFBCModels = "0.1, 0.2"
 DocStringExtensions = "0.8, 0.9"
 MAT = "0.10"
+SparseArrays = "1"
+Test = "1"
+julia = "1"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
diff --git a/src/MATFBCModels.jl b/src/MATFBCModels.jl
index 36e1185..51eab18 100644
--- a/src/MATFBCModels.jl
+++ b/src/MATFBCModels.jl
@@ -1,14 +1,17 @@
 module MATFBCModels
 
 using DocStringExtensions
+
 import AbstractFBCModels as A
-using MAT, SparseArrays
+
+using MAT
+using SparseArrays
 
 include("types.jl")
 include("constants.jl")
-include("utils.jl")
 include("interface.jl")
 include("io.jl")
+include("utils.jl")
 
 export MATFBCModel
 
diff --git a/src/utils.jl b/src/utils.jl
index 9b10319..ea43227 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -44,10 +44,10 @@ end
 function unparse_formula(x::Maybe{A.MetaboliteFormula})
     isnothing(x) && return nothing
     ks = sort(collect(keys(x)))
-    join([k * string(x[k]) for k in ks])
+    join(k * string(x[k]) for k in ks)
 end
 
 function unparse_grr(xs::Maybe{A.GeneAssociationDNF})
     isnothing(xs) && return nothing
-    join([join(x, " and ") for x in xs], " or ")
+    join((join(x, " and ") for x in xs), " or ")
 end