diff --git a/mapytex/calculus/API/expression.py b/mapytex/calculus/API/expression.py
index 1403004..bc897d0 100644
--- a/mapytex/calculus/API/expression.py
+++ b/mapytex/calculus/API/expression.py
@@ -13,7 +13,7 @@ Expression
 from ..core import AssocialTree, Tree, compute, typing, TypingError
 from ..core.random import extract_rdleaf, extract_rv, random_generator, compute_leafs, replace_rdleaf
 from ..core.MO import moify
-from .tokens import factory, Token
+from .tokens import factory
 from .renders import renders
 
 
@@ -73,6 +73,7 @@ class Expression(object):
         \\frac{11}{4}
         >>> Expression.set_render('txt')
         """
+        from .tokens.token import Token
         Token.set_render(render)
         cls.RENDER = render
 
diff --git a/mapytex/calculus/API/tokens/__init__.py b/mapytex/calculus/API/tokens/__init__.py
index 49b796b..7163976 100644
--- a/mapytex/calculus/API/tokens/__init__.py
+++ b/mapytex/calculus/API/tokens/__init__.py
@@ -16,11 +16,6 @@ from ...core.MO.monomial import MOstrPower, MOMonomial
 from ...core.MO.polynomial import MOpolynomial
 from decimal import Decimal as _Decimal
 
-from .number import Integer, Decimal, Fraction
-from .polynomial import Polynomial, Linear, Quadratic
-
-from .token import Token
-
 __all__ = ["factory"]
 
 
@@ -63,8 +58,10 @@ def factory(exp, name="", ancestor=None):
 
     if isinstance(mo, MOnumber):
         if isinstance(mo.value, int):
+            from .number import Integer
             return Integer.from_mo(mo, name, ancestor)
         elif isinstance(mo.value, _Decimal):
+            from .number import Decimal
             return Decimal.from_mo(mo, name, ancestor)
 
         raise TypeError(f"Can't build from MOnumber ({mo}) neither int nor decimal")
@@ -73,6 +70,7 @@ def factory(exp, name="", ancestor=None):
         if isinstance(mo._denominator, MOnumber) and isinstance(
             mo._numerator, MOnumber
         ):
+            from .number import Fraction
             return Fraction.from_mo(mo, name, ancestor)
 
         raise TypeError(
@@ -89,14 +87,17 @@ def factory(exp, name="", ancestor=None):
             or (isinstance(mo, MOMonomial) and mo.power.value == 1)
             or (isinstance(mo, MOpolynomial) and mo.power.value == 1)
         ):
+            from .polynomial import Linear
             return Linear.from_mo(mo, name, ancestor)
         elif (
             (isinstance(mo, MOstrPower) and mo.power.value == 2)
             or (isinstance(mo, MOMonomial) and mo.power.value == 2)
             or (isinstance(mo, MOpolynomial) and mo.power.value == 2)
         ):
+            from .polynomial import Quadratic
             return Quadratic.from_mo(mo, name, ancestor)
         else:
+            from .polynomial import Polynomial
             return Polynomial.from_mo(mo, name, ancestor)
 
     else: