diff --git a/mathics/builtin/intfns/combinatorial.py b/mathics/builtin/intfns/combinatorial.py
index ae3c4df0e..a468aac24 100644
--- a/mathics/builtin/intfns/combinatorial.py
+++ b/mathics/builtin/intfns/combinatorial.py
@@ -416,9 +416,9 @@ class PolygonalNumber(Builtin):
 
     See also <url>
     :Binomial:
-    doc/reference-of-built-in-symbols/integer-functions/combinatorial-functions/binomial/</url>, and <url>
+    /doc/reference-of-built-in-symbols/integer-functions/combinatorial-functions/binomial/</url>, and <url>
     :RegularPolygon:
-    doc/reference-of-built-in-symbols/drawing-graphics/regularpolygon/</url>.
+    /doc/reference-of-built-in-symbols/drawing-graphics/regularpolygon/</url>.
     """
 
     attributes = A_LISTABLE | A_NUMERIC_FUNCTION | A_PROTECTED | A_READ_PROTECTED
diff --git a/mathics/builtin/numbers/calculus.py b/mathics/builtin/numbers/calculus.py
index 0efd55114..80bb3ef7a 100644
--- a/mathics/builtin/numbers/calculus.py
+++ b/mathics/builtin/numbers/calculus.py
@@ -952,8 +952,10 @@ class Integers(Builtin):
 
 class Integrate(SympyFunction):
     r"""
-    <url>:WMA link:
-    https://reference.wolfram.com/language/ref/Integrate.html</url>
+    <url>:Integral:https://en.wikipedia.org/wiki/Integral</url> (<url>:SymPy:
+    https://docs.sympy.org/latest/modules/integrals/integrals.html</url>, \
+    <url>:WMA:
+    https://reference.wolfram.com/language/ref/Integrate.html</url>)
 
     <dl>
       <dt>'Integrate[$f$, $x$]'
@@ -984,18 +986,20 @@ class Integrate(SympyFunction):
     >> Integrate[4 Sin[x] Cos[x], x]
      = 2 Sin[x] ^ 2
 
-    > Integrate[-Infinity, {x, 0, Infinity}]
+    >> Integrate[-Infinity, {x, 0, Infinity}]
      = -Infinity
 
-    > Integrate[-Infinity, {x, Infinity, 0}]
-     = Infinity
+    Integrating something ill-defined returns the expression untouched:
 
-    Integration in TeX:
+    >> Integrate[1, {x, Infinity, 0}]
+     = Integrate[1, {x, Infinity, 0}]
+
+    Here how is an example of converting integral equation to TeX:
     >> Integrate[f[x], {x, a, b}] // TeXForm
      = \int_a^b f\left[x\right] \, dx
 
     Sometimes there is a loss of precision during integration.
-    You can check the precision of your result with the following sequence
+    You can check the precision of your result with the following sequence \
     of commands.
     >> Integrate[Abs[Sin[phi]], {phi, 0, 2Pi}] // N
      = 4.
@@ -1114,6 +1118,10 @@ def eval(self, f, xs, evaluation: Evaluation, options: dict):  # type: ignore[ov
             # e.g. NotImplementedError: Result depends on the sign of
             # -sign(_u`j)*sign(_u`w)
             return
+        except TypeError:
+            # SymPy can give this. For example:
+            # Integrate[-Infinity, {x, 0, Infinity}]
+            return
         if prec is not None and isinstance(sympy_result, sympy.Integral):
             # TODO MaxExtraPrecision -> maxn
             sympy_result = sympy_result.evalf(dps(prec))