diff --git a/src/JuliaFEM.jl b/src/JuliaFEM.jl
index 4cc6e04..da50480 100644
--- a/src/JuliaFEM.jl
+++ b/src/JuliaFEM.jl
@@ -167,12 +167,12 @@ export constitutive_matrix_plate, get_thickness
 
 # Note: domains/plates/dkt.jl is included later after Mesh is defined (line ~430)
 
-# Physics domain API (abstract type and interface functions)
-include("physics/api.jl")
+# Physics domain API (abstract type, interface functions, and concrete implementations)
+include("physics/abstract.jl")       # AbstractPhysics abstract type
+include("physics/api.jl")            # Interface functions (assemble!, solve!, etc.)
+include("physics/types.jl")          # Physics struct, DirichletBC, NeumannBC, Constraint
+include("physics/boundary_conditions.jl")  # BC method implementations
 export AbstractPhysics, assemble!, solve!, add_dirichlet!, add_neumann!
-
-# Concrete Physics implementation (uses abstractions from physics/api.jl)
-include("physics.jl")
 export Physics, Constraint, DirichletBC, NeumannBC
 
 # Export additional assembly functions
@@ -278,7 +278,7 @@ include("basis/lagrange_generator.jl")
 include("basis/lagrange_generated.jl")  # Auto-generated by: julia --project=. src/basis/lagrange_generator.jl
 
 # Plate element basis functions (DKT, DST, etc.)
-include("basis/plate_elements.jl")  # AbstractPlateBasis, DKT
+include("domains/plates/dkt_basis.jl")  # AbstractPlateBasis, DKT
 
 # Export basis types and functions (OLD API)
 export AbstractBasis, Lagrange, Serendipity