diff --git a/Project.toml b/Project.toml
index f8bd0ac..ffe8273 100644
--- a/Project.toml
+++ b/Project.toml
@@ -23,7 +23,7 @@ TensorOperations = "6aa20fa7-93e2-5fca-9bc0-fbd0db3c71a2"
 WhereTraits = "c9d4e05b-6318-49cb-9b56-e0e2b0ceadd8"
 
 [compat]
-Bijections = "0.1"
+Bijections = "0.2"
 DataStructures = "0.18, 0.19"
 Distributions = "0.25"
 Graphs = "1"
diff --git a/src/abstractmultilayergraph.jl b/src/abstractmultilayergraph.jl
index 6e3e315..be9b9d7 100644
--- a/src/abstractmultilayergraph.jl
+++ b/src/abstractmultilayergraph.jl
@@ -51,7 +51,7 @@ fadjlist(mg::AbstractMultilayerGraph) = mg.fadjlist
 Return the nodes of the AbstractMultilayerGraph `mg`, in order of addition.
 """
 function nodes(mg::AbstractMultilayerGraph)
-    return [couple[2] for couple in sort(collect(mg.idx_N_associations); by=first)]
+    return Node[node for (_, node) in sort!(collect(mg.idx_N_associations); by=first)]
 end
 
 """
diff --git a/src/multilayerdigraph.jl b/src/multilayerdigraph.jl
index 4f93bfe..ff31f14 100644
--- a/src/multilayerdigraph.jl
+++ b/src/multilayerdigraph.jl
@@ -7,7 +7,7 @@ mutable struct MultilayerDiGraph{T,U} <: AbstractMultilayerGraph{T,U}
     layers::Vector{LayerDescriptor{T,U}} # vector containing all the layers of the multilayer graph. Their underlying graphs must be all undirected.
     interlayers::OrderedDict{Set{Symbol},InterlayerDescriptor{T,U}} #  the ordered dictionary containing all the interlayers of the multilayer graph. Their underlying graphs must be all undirected.
     v_V_associations::Bijection{T,<:MultilayerVertex} # A Bijection from Bijections.jl that associates numeric vertices to `MultilayerVertex`s.
-    idx_N_associations::Bijection{Int64,Node} # A Bijection from Bijections.jl that associates Int64 to `Node`s.
+    idx_N_associations::Bijection{Int64,Node,Dict{Int64,Node},Dict{Node,Int64}} # A Bijection from Bijections.jl that associates Int64 to `Node`s.
     fadjlist::Vector{Vector{HalfEdge{<:MultilayerVertex,<:Union{Nothing,U}}}} # the forward adjacency list of the MultilayerDiGraph. It is a vector of vectors of `HalfEdge`s. Its i-th element are the `HalfEdge`s that originate from `v_V_associations[i]`.
     badjlist::Vector{Vector{HalfEdge{<:MultilayerVertex,<:Union{Nothing,U}}}} # the backward adjacency list of the MultilayerDiGraph. It is a vector of vectors of `HalfEdge`s. Its i-th element are the `HalfEdge`s that insist on `v_V_associations[i]`.
     v_metadata_dict::Dict{T,<:Union{<:Tuple,<:NamedTuple}} # A Dictionary that associates numeric vertices to their metadata
diff --git a/src/multilayergraph.jl b/src/multilayergraph.jl
index 4b21deb..4eab5e0 100644
--- a/src/multilayergraph.jl
+++ b/src/multilayergraph.jl
@@ -7,7 +7,7 @@ mutable struct MultilayerGraph{T,U} <: AbstractMultilayerGraph{T,U}
     layers::Vector{LayerDescriptor{T,U}} # vector containing all the layers of the multilayer graph. Their underlying graphs must be all undirected.
     interlayers::OrderedDict{Set{Symbol},InterlayerDescriptor{T,U}} # the ordered dictionary containing all the interlayers of the multilayer graph. Their underlying graphs must be all undirected.
     v_V_associations::Bijection{T,<:MultilayerVertex} # A Bijection from Bijections.jl that associates numeric vertices to `MultilayerVertex`s.
-    idx_N_associations::Bijection{Int64,Node} # A Bijection from Bijections.jl that associates Int64 to `Node`s.
+    idx_N_associations::Bijection{Int64,Node,Dict{Int64,Node},Dict{Node,Int64}} # A Bijection from Bijections.jl that associates Int64 to `Node`s.
     fadjlist::Vector{Vector{HalfEdge{<:MultilayerVertex,<:Union{Nothing,U}}}} # the forward adjacency list of the MultilayerGraph. It is a vector of vectors of `HalfEdge`s. Its i-th element are the `HalfEdge`s that originate from `v_V_associations[i]`.
     v_metadata_dict::Dict{T,<:Union{<:Tuple,<:NamedTuple}} #  A Dictionary that associates numeric vertices to their metadata.
 end