diff --git a/include/angle.h b/include/angle.h
index f86cf18..9787bc9 100644
--- a/include/angle.h
+++ b/include/angle.h
@@ -1172,7 +1172,7 @@ class angle_distribution
     AM_CHECK_NARROWING(typename Turn::type,typename ValueDistr::result_type)
 
 public:
-    using param_type   = num::param_t<ValueDistr>;
+    using param_type   = typename ValueDistr::param_type;
     using numeric_type = typename ValueDistr::result_type;
     using result_type  = angle<Turn>;
 
@@ -1265,7 +1265,7 @@ class uniform_angle_distribution :
 public:
     //---------------------------------------------------------------
     using numeric_type = typename Turn::type;
-    using param_type = num::param_t<base_t_>;
+    using param_type   = typename base_t_::param_type;
 
     //---------------------------------------------------------------
     explicit
diff --git a/include/distributions.h b/include/distributions.h
index 717fa0a..254e4ca 100644
--- a/include/distributions.h
+++ b/include/distributions.h
@@ -57,13 +57,11 @@ using uniform_number_distribution = typename
 
 
 
-
 /*****************************************************************************
  *
  *
  *
  *
- *
  *****************************************************************************/
 template<class Result, class ValueDistribution>
 class distribution_adapter
@@ -73,7 +71,7 @@ class distribution_adapter
 public:
     //---------------------------------------------------------------
     using result_type = Result;
-    using param_type = param_t<ValueDistribution>;
+    using param_type = typename ValueDistribution::param_type;
 
 
     //---------------------------------------------------------------
@@ -163,9 +161,7 @@ using uniform_distribution_adapter =
     distribution_adapter<Result, uniform_number_distribution<numeric_t<Result>> >;
 
 
-
 }  // namespace num
-
 }  // namespace am
 
 #endif // AMLIB_GEOMETRY_CREATION_POINTS_H_
diff --git a/include/param.h b/include/param.h
deleted file mode 100644
index 199889d..0000000
--- a/include/param.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/*****************************************************************************
- *
- * AM numeric facilities
- *
- * released under MIT license
- *
- * 2008-2017 André Müller
- *
- *****************************************************************************/
-
-#ifndef AMLIB_NUMERIC_PARAM_H_
-#define AMLIB_NUMERIC_PARAM_H_
-
-
-#include <type_traits>
-
-
-namespace am {
-namespace num {
-
-
-namespace detail {
-
-//-------------------------------------------------------------------
-template<class T>
-constexpr auto
-check_has_param(int)
-    -> decltype(
-        std::declval<typename T::param_type>(),
-        std::declval<T>().param(),
-        std::true_type{});
-//---------------------------------------------------------
-template<class>
-constexpr auto
-check_has_param(long)
-    -> std::false_type;
-
-}  // namespace detail
-
-
-
-//-------------------------------------------------------------------
-template<class T>
-struct has_param : public
-    decltype(detail::check_has_param<T>(0))
-{};
-
-
-
-//-------------------------------------------------------------------
-template<class T, bool has = has_param<T>::value>
-struct param {
-    using type = T;
-};
-
-template<class T>
-struct param<T,true> {
-    using type = typename T::param_type;
-};
-
-template<class T>
-using param_t = typename param<T>::type;
-
-
-
-}  // namespace num
-}  // namespace am
-
-
-#endif