diff --git a/Project.toml b/Project.toml
index ad83249..9fdfe6e 100644
--- a/Project.toml
+++ b/Project.toml
@@ -12,6 +12,7 @@ RateTables = "d40fb65e-c2ee-4113-9e14-cb96ca0acb32"
 StatsAPI = "82ae8749-77ed-4fe6-ae5f-f523153014b0"
 StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 StatsModels = "3eaba693-59b7-5ba5-a881-562e759f1c8d"
+SurvivalBase = "9cb6079b-e021-4662-8a75-9f65bfa286f2"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 
 [compat]
@@ -19,8 +20,8 @@ CSV = "0.10"
 DataFrames = "1"
 Distributions = "0.25"
 LinearAlgebra = "1.6"
-RateTables = "0.1.1"
 RCall = "0.14"
+RateTables = "0.1.1"
 StatsAPI = "1"
 StatsBase = "0.34"
 StatsModels = "0.7"
diff --git a/src/NetSurvival.jl b/src/NetSurvival.jl
index a0dc006..f14d4b7 100644
--- a/src/NetSurvival.jl
+++ b/src/NetSurvival.jl
@@ -5,14 +5,14 @@ using Distributions
 using LinearAlgebra
 using StatsAPI
 using StatsBase
-using StatsModels
 using Tables
 using Base.Cartesian
 using CSV
 using RateTables
+using StatsModels
+using SurvivalBase: Surv, Strata
 
 include("fetch_datasets.jl")
-include("Surv_and_Strata.jl")
 include("Nessie.jl")
 include("NPNSEstimator.jl")
 include("PoharPerme.jl")
diff --git a/src/Surv_and_Strata.jl b/src/Surv_and_Strata.jl
deleted file mode 100644
index 29f69ae..0000000
--- a/src/Surv_and_Strata.jl
+++ /dev/null
@@ -1,74 +0,0 @@
-# struct for behavior
-# struct Surv{X, Y}
-#     T::X
-#     Δ::Y
-# end
-struct SurvTerm{X, Y} <: AbstractTerm
-    T::X
-    Δ::Y
-    function SurvTerm(T,Δ)
-        return new{typeof(T),typeof(Δ)}(T, Δ)
-    end
-end
-# Base.show(io::IO, t::Surv) = print(io, string(t.T,  t.Δ == 1 ? "+" : ""))
-Base.show(io::IO, t::SurvTerm) = print(io, "Surv($((t.T, t.Δ)))")
-
-
-# Surv(T::Symbol, Δ::Symbol) = SurvTerm(term(T), term(Δ))
-Surv(T::Float64, Δ::Bool) = (T, Δ)
-
-Strata(x) = x
-struct StrataTerm{X} <: AbstractTerm
-    Covariable::X
-end
-Base.show(io::IO, t::StrataTerm) = print(io, "Strata($((t.Covariable)))")
-
-Strata(Covariables::Vector) = StrataTerm(term(Covariables))
-
-StatsModels.termvars(p::StrataTerm) = StatsModels.termvars(p.Covariable)
-
-
-function StatsModels.apply_schema(t::FunctionTerm{typeof(Surv)},
-    sch::StatsModels.Schema,
-    Mod::Type{<:Any})
-    return apply_schema(SurvTerm(t.args...), sch, Mod) 
-end
-
-function StatsModels.apply_schema(t::FunctionTerm{typeof(Strata)},
-    sch::StatsModels.Schema,
-    Mod::Type{<:Any})
-    return apply_schema(StrataTerm(t.args...), sch, Mod) 
-end
-
-function StatsModels.apply_schema(t::SurvTerm{X,Y},
-    sch::StatsModels.Schema,
-    Mod::Type{<:Any}) where {X,Y}
-    T = apply_schema(t.T, sch, Mod)
-    Δ = apply_schema(t.Δ, sch, Mod)
-    isa(T, ContinuousTerm) || throw(ArgumentError("Surv only works with continuous terms (got $T)"))
-    isa(Δ, ContinuousTerm) ||  throw(ArgumentError("Surv only works with discrete terms (got $Δ)"))
-    return SurvTerm(T, Δ)
-end
-
-function StatsModels.apply_schema(t::StrataTerm,
-    sch::StatsModels.Schema,
-    Mod::Type{<:Any})
-    X = apply_schema(t.Covariable, sch, Mod)
-    return StrataTerm(X)
-end
-
-function StatsModels.modelcols(t::SurvTerm, d::NamedTuple)
-    T = modelcols(t.T, d)
-    Δ = modelcols(t.Δ, d)
-    return hcat(T,Δ)
-end
-
-function StatsModels.modelcols(t::StrataTerm, d::NamedTuple)
-    return modelcols(t.Covariable, d)
-end
-
-
-
-
-
-