@Article{stochasticProcessesFourierTransforms,

 author = {Hannu Niemi},
 title = {Stochastic processes as Fourier transforms of stochastic
measures},
 year = {1975},
 journal = {Annales Fennici Mathematici},
 number = {591}}

 #253

src/main/java/arb/expressions/nodes/DerivativeNode.java

@@ -165,8 +165,7 @@ public <C> Class<? extends C> type()
          Node<E, S, G>
          spliceInto(Expression<E, S, G> newExpression)
   {
-    assert false : "TODO: https://github.com/crowlogic/arb4j/issues/540";
-    return null;
+    return derivative.spliceInto(newExpression);
   }
 
   @Override