diff --git a/povm_toolbox/library/randomized_projective_measurements.py b/povm_toolbox/library/randomized_projective_measurements.py
index 4cc532e..ff021b9 100644
--- a/povm_toolbox/library/randomized_projective_measurements.py
+++ b/povm_toolbox/library/randomized_projective_measurements.py
@@ -30,8 +30,7 @@
 from qiskit.primitives.containers.sampler_pub import SamplerPub
 from qiskit.transpiler import StagedPassManager
 
-from povm_toolbox.quantum_info.product_povm import ProductPOVM
-from povm_toolbox.quantum_info.single_qubit_povm import SingleQubitPOVM
+from povm_toolbox.quantum_info import ProductPOVM, SingleQubitPOVM
 
 from .metadata import RPMMetadata
 from .povm_implementation import POVMImplementation
diff --git a/povm_toolbox/post_processor/dual_from_empirical_frequencies.py b/povm_toolbox/post_processor/dual_from_empirical_frequencies.py
index 8c7a242..d83d083 100644
--- a/povm_toolbox/post_processor/dual_from_empirical_frequencies.py
+++ b/povm_toolbox/post_processor/dual_from_empirical_frequencies.py
@@ -18,9 +18,8 @@
 from qiskit.quantum_info import DensityMatrix, SparsePauliOp, Statevector
 
 from povm_toolbox.post_processor.povm_post_processor import POVMPostProcessor
-from povm_toolbox.quantum_info import ProductPOVM
+from povm_toolbox.quantum_info import ProductDual, ProductPOVM
 from povm_toolbox.quantum_info.base import BaseDual
-from povm_toolbox.quantum_info.product_dual import ProductDual
 
 
 def dual_from_empirical_frequencies(
diff --git a/povm_toolbox/post_processor/dual_from_marginal_probabilities.py b/povm_toolbox/post_processor/dual_from_marginal_probabilities.py
index 23f7ac0..923fcf3 100644
--- a/povm_toolbox/post_processor/dual_from_marginal_probabilities.py
+++ b/povm_toolbox/post_processor/dual_from_marginal_probabilities.py
@@ -17,9 +17,8 @@
 import numpy as np
 from qiskit.quantum_info import DensityMatrix, SparsePauliOp, Statevector
 
-from povm_toolbox.quantum_info import ProductPOVM
+from povm_toolbox.quantum_info import ProductDual, ProductPOVM
 from povm_toolbox.quantum_info.base import BaseDual, BasePOVM
-from povm_toolbox.quantum_info.product_dual import ProductDual
 
 
 def dual_from_marginal_probabilities(
diff --git a/povm_toolbox/post_processor/dual_from_state.py b/povm_toolbox/post_processor/dual_from_state.py
index f1b06b6..4d8869d 100644
--- a/povm_toolbox/post_processor/dual_from_state.py
+++ b/povm_toolbox/post_processor/dual_from_state.py
@@ -17,9 +17,8 @@
 import numpy as np
 from qiskit.quantum_info import DensityMatrix, SparsePauliOp, Statevector
 
-from povm_toolbox.quantum_info import MultiQubitPOVM
+from povm_toolbox.quantum_info import MultiQubitDual, MultiQubitPOVM
 from povm_toolbox.quantum_info.base import BaseDual, BasePOVM
-from povm_toolbox.quantum_info.multi_qubit_dual import MultiQubitDual
 
 
 def dual_from_state(