diff --git a/src/debug.jl b/src/debug.jl
index 3593779..9daddd9 100644
--- a/src/debug.jl
+++ b/src/debug.jl
@@ -1,5 +1,15 @@
 
 using .BipartiteGraphs: Label, BipartiteAdjacencyList
+
+struct SSAUses{T}
+    eqs::Vector{T} # equation uses
+    vars::Vector{T} # variable uses
+end
+Base.eltype(info::SSAUses{T}) where {T} = T
+Base.copy(uses::SSAUses) = SSAUses(copy(uses.eqs), copy(uses.vars))
+
+ssa_uses(::SystemStructure) = nothing
+
 struct SystemStructurePrintMatrix <:
        AbstractMatrix{Union{Label, BipartiteAdjacencyList}}
     bpg::BipartiteGraph
@@ -7,6 +17,7 @@ struct SystemStructurePrintMatrix <:
     var_to_diff::DiffGraph
     eq_to_diff::DiffGraph
     var_eq_matching::Union{Matching, Nothing}
+    ssa_uses::Union{Nothing, SSAUses}
 end
 
 """
@@ -19,31 +30,36 @@ function SystemStructurePrintMatrix(s::SystemStructure)
         complete(s.solvable_graph),
         complete(s.var_to_diff),
         complete(s.eq_to_diff),
-        nothing)
+        nothing,
+        ssa_uses(s))
 end
-Base.size(bgpm::SystemStructurePrintMatrix) = (max(nsrcs(bgpm.bpg), ndsts(bgpm.bpg)) + 1, 9)
+Base.size(bgpm::SystemStructurePrintMatrix) = (max(nsrcs(bgpm.bpg), ndsts(bgpm.bpg)) + 1, 9 + 2(bgpm.ssa_uses !== nothing))
 function compute_diff_label(diff_graph, i, symbol)
     di = i - 1 <= length(diff_graph) ? diff_graph[i - 1] : nothing
     return di === nothing ? Label("") : Label(string(di, symbol))
 end
 function Base.getindex(bgpm::SystemStructurePrintMatrix, i::Integer, j::Integer)
     checkbounds(bgpm, i, j)
+    if bgpm.ssa_uses === nothing
+        # Skip SSAUse-related columns.
+        j += j ≥ 5 + j ≥ 11
+    end
     if i <= 1
-        return (Label.(("# eq", "∂ₜ", " ", " ", "", "# v", "∂ₜ", " ", " ")))[j]
-    elseif j == 5
+        return (Label.(("# eq", "∂ₜ", " ", " ", "%", "", "# v", "∂ₜ", " ", " ", "%")))[j]
+    elseif j == 6
         colors = Base.text_colors
         return Label("|", :light_black)
     elseif j == 2
         return compute_diff_label(bgpm.eq_to_diff, i, '↑')
     elseif j == 3
         return compute_diff_label(invview(bgpm.eq_to_diff), i, '↓')
-    elseif j == 7
-        return compute_diff_label(bgpm.var_to_diff, i, '↑')
     elseif j == 8
+        return compute_diff_label(bgpm.var_to_diff, i, '↑')
+    elseif j == 9
         return compute_diff_label(invview(bgpm.var_to_diff), i, '↓')
     elseif j == 1
         return Label((i - 1 <= length(bgpm.eq_to_diff)) ? string(i - 1) : "")
-    elseif j == 6
+    elseif j == 7
         return Label((i - 1 <= length(bgpm.var_to_diff)) ? string(i - 1) : "")
     elseif j == 4
         return BipartiteAdjacencyList(
@@ -56,7 +72,11 @@ function Base.getindex(bgpm::SystemStructurePrintMatrix, i::Integer, j::Integer)
             bgpm.var_eq_matching !== nothing &&
             (i - 1 <= length(invview(bgpm.var_eq_matching))) ?
             invview(bgpm.var_eq_matching)[i - 1] : unassigned)
-    elseif j == 9
+    elseif j == 5
+        return get(bgpm.ssa_uses.eqs, i - 1, Label(""))
+    elseif j == 11
+        return get(bgpm.ssa_uses.vars, i - 1, Label(""))
+    elseif j == 10
         match = unassigned
         if bgpm.var_eq_matching !== nothing && i - 1 <= length(bgpm.var_eq_matching)
             match = bgpm.var_eq_matching[i - 1]
@@ -95,7 +115,11 @@ end
 struct MatchedSystemStructure
     structure::SystemStructure
     var_eq_matching::Matching
+    ssa_uses::Union{Nothing, SSAUses}
 end
+MatchedSystemStructure(structure, var_eq_matching) = MatchedSystemStructure(structure, var_eq_matching, nothing)
+
+ssa_uses(ms::MatchedSystemStructure) = ms.ssa_uses
 
 """
 Create a SystemStructurePrintMatrix to display the contents
@@ -106,12 +130,12 @@ function SystemStructurePrintMatrix(ms::MatchedSystemStructure)
         complete(ms.structure.solvable_graph),
         complete(ms.structure.var_to_diff),
         complete(ms.structure.eq_to_diff),
-        complete(ms.var_eq_matching,
-            nsrcs(ms.structure.graph)))
+        complete(ms.var_eq_matching, nsrcs(ms.structure.graph)),
+        ms.ssa_uses)
 end
 
 function Base.copy(ms::MatchedSystemStructure)
-    MatchedSystemStructure(Base.copy(ms.structure), Base.copy(ms.var_eq_matching))
+    MatchedSystemStructure(copy(ms.structure), copy(ms.var_eq_matching), copy(ms.ssa_uses))
 end
 
 function Base.show(io::IO, mime::MIME"text/plain", ms::MatchedSystemStructure)
@@ -136,4 +160,11 @@ function Base.show(io::IO, mime::MIME"text/plain", ms::MatchedSystemStructure)
         printstyled(io, string(" ", symbol); color)
         printstyled(io, string(" ", label))
     end
+    if ms.ssa_uses !== nothing
+        T = eltype(ms.ssa_uses)
+        (symbol, label, color) = BipartiteGraphs.overview_label(T)
+        print(io, " | ")
+        printstyled(io, string(" ", symbol); color)
+        printstyled(io, string(" ", label))
+    end
 end
diff --git a/src/interface.jl b/src/interface.jl
index 1cd7523..a572fca 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -5,7 +5,7 @@ abstract type TransformationState{T} end
 abstract type AbstractTearingState{T} <: TransformationState{T} end
 
 struct SelectedState end
-BipartiteGraphs.overview_label(::Type{SelectedState}) = ('∫', " Seleced State", :cyan)
+BipartiteGraphs.overview_label(::Type{SelectedState}) = ('∫', " Selected State", :cyan)
 
 function linear_subsys_adjmat! end
 function eq_derivative! end