diff --git a/src/alchemy.c b/src/alchemy.c
index 86f6e6bb6..5419be4ee 100644
--- a/src/alchemy.c
+++ b/src/alchemy.c
@@ -21,6 +21,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "alchemy.h"
 #include "move.h"
 #include "skill.h"
+#include "study.h"
 
 #include <kernel/item.h>
 #include <kernel/faction.h>
diff --git a/src/economy.c b/src/economy.c
index 6311d0c3a..2156744b0 100644
--- a/src/economy.c
+++ b/src/economy.c
@@ -28,6 +28,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "laws.h"
 #include "randenc.h"
 #include "spy.h"
+#include "study.h"
 #include "move.h"
 #include "monster.h"
 #include "morale.h"
diff --git a/src/kernel/build.c b/src/kernel/build.c
index 98ca2b28e..3d4fb6a17 100644
--- a/src/kernel/build.c
+++ b/src/kernel/build.c
@@ -23,6 +23,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "alchemy.h"
 #include "direction.h"
 #include "move.h"
+#include "study.h"
 #include "laws.h"
 #include "skill.h"
 #include "lighthouse.h"
diff --git a/src/kernel/unit.c b/src/kernel/unit.c
index 5fc797e25..411c460e7 100644
--- a/src/kernel/unit.c
+++ b/src/kernel/unit.c
@@ -28,7 +28,6 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "curse.h"
 #include "item.h"
 #include "move.h"
-#include "monster.h"
 #include "order.h"
 #include "plane.h"
 #include "race.h"
@@ -1892,25 +1891,6 @@ bool unit_can_study(const unit *u) {
     return !((u_race(u)->flags & RCF_NOLEARN) || fval(u, UFL_WERE));
 }
 
-static double produceexp_chance(void) {
-    return config_get_flt("study.from_use", 1.0 / 3);
-}
-
-void produceexp_ex(struct unit *u, skill_t sk, int n, bool(*learn)(unit *, skill_t, double))
-{
-    if (n != 0 && (is_monsters(u->faction) || playerrace(u_race(u)))) {
-        double chance = produceexp_chance();
-        if (chance > 0.0F) {
-            learn(u, sk, (n * chance) / u->number);
-        }
-    }
-}
-
-void produceexp(struct unit *u, skill_t sk, int n)
-{
-    produceexp_ex(u, sk, n, learn_skill);
-}
-
 /* ID's für Einheiten und Zauber */
 int newunitid(void)
 {
diff --git a/src/kernel/unit.h b/src/kernel/unit.h
index 36abb1cf3..835b5264b 100644
--- a/src/kernel/unit.h
+++ b/src/kernel/unit.h
@@ -162,9 +162,6 @@ extern "C" {
     struct skill *unit_skill(const struct unit *u, skill_t id);
     bool has_skill(const unit * u, skill_t sk);
     int effskill(const struct unit *u, skill_t sk, const struct region *r);
-    int SkillCap(skill_t sk);
-    void produceexp(struct unit *u, skill_t sk, int n);
-    void produceexp_ex(struct unit *u, skill_t sk, int n, bool (*learn)(unit *, skill_t, double));
 
     void set_level(struct unit *u, skill_t id, int level);
     int get_level(const struct unit *u, skill_t id);
diff --git a/src/kernel/unit.test.c b/src/kernel/unit.test.c
index 474d839ee..807a27327 100644
--- a/src/kernel/unit.test.c
+++ b/src/kernel/unit.test.c
@@ -341,32 +341,6 @@ static void test_age_familiar(CuTest *tc) {
     test_cleanup();
 }
 
-static CuTest *g_tc;
-
-static bool cb_learn_one(unit *u, skill_t sk, double chance) {
-    CuAssertIntEquals(g_tc, SK_ALCHEMY, sk);
-    CuAssertDblEquals(g_tc, 0.5 / u->number, chance, 0.01);
-    return false;
-}
-
-static bool cb_learn_two(unit *u, skill_t sk, double chance) {
-    CuAssertIntEquals(g_tc, SK_ALCHEMY, sk);
-    CuAssertDblEquals(g_tc, 2 * 0.5 / u->number, chance, 0.01);
-    return false;
-}
-
-static void test_produceexp(CuTest *tc) {
-    unit *u;
-
-    g_tc = tc;
-    test_cleanup();
-    u = test_create_unit(test_create_faction(0), test_create_region(0, 0, 0));
-    config_set("study.from_use", "0.5");
-    produceexp_ex(u, SK_ALCHEMY, 1, cb_learn_one);
-    produceexp_ex(u, SK_ALCHEMY, 2, cb_learn_two);
-    test_cleanup();
-}
-
 static void test_inside_building(CuTest *tc) {
     unit *u;
     building *b;
@@ -433,7 +407,6 @@ CuSuite *get_unit_suite(void)
     SUITE_ADD_TEST(suite, test_skill_familiar);
     SUITE_ADD_TEST(suite, test_age_familiar);
     SUITE_ADD_TEST(suite, test_inside_building);
-    SUITE_ADD_TEST(suite, test_produceexp);
     SUITE_ADD_TEST(suite, test_limited_skills);
     return suite;
 }
diff --git a/src/magic.c b/src/magic.c
index e7d94ac25..d24612e06 100644
--- a/src/magic.c
+++ b/src/magic.c
@@ -22,6 +22,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "magic.h"
 
 #include "skill.h"
+#include "study.h"
 #include "laws.h"
 
 #include <kernel/ally.h>
diff --git a/src/monsters.c b/src/monsters.c
index 634c6db54..40f42f2f1 100644
--- a/src/monsters.c
+++ b/src/monsters.c
@@ -26,6 +26,7 @@
 #include "monster.h"
 #include "laws.h"
 #include "keyword.h"
+#include "study.h"
 
 /* triggers includes */
 #include <triggers/removecurse.h>
diff --git a/src/monsters.test.c b/src/monsters.test.c
index 9fce059f2..c619ecf2a 100644
--- a/src/monsters.test.c
+++ b/src/monsters.test.c
@@ -13,6 +13,7 @@
 #include "monster.h"
 #include "guard.h"
 #include "skill.h"
+#include "study.h"
 
 #include <util/language.h>
 
diff --git a/src/move.c b/src/move.c
index 456610866..e602b073c 100644
--- a/src/move.c
+++ b/src/move.c
@@ -22,6 +22,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "move.h"
 #include "laws.h"
 #include "reports.h"
+#include "study.h"
 #include "alchemy.h"
 #include "travelthru.h"
 #include "vortex.h"
diff --git a/src/spy.c b/src/spy.c
index e25ff1e85..9b8fe4601 100644
--- a/src/spy.c
+++ b/src/spy.c
@@ -22,6 +22,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "laws.h"
 #include "move.h"
 #include "reports.h"
+#include "study.h"
 
 /* kernel includes */
 #include <kernel/item.h>
diff --git a/src/study.c b/src/study.c
index 9335519a6..b7ea62786 100644
--- a/src/study.c
+++ b/src/study.c
@@ -23,6 +23,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <kernel/config.h>
 #include "study.h"
 #include "move.h"
+#include "monster.h"
 #include "alchemy.h"
 
 #include <kernel/ally.h>
@@ -804,3 +805,22 @@ int study_cmd(unit * u, order * ord)
 
     return 0;
 }
+
+static double produceexp_chance(void) {
+    return config_get_flt("study.from_use", 1.0 / 3);
+}
+
+void produceexp_ex(struct unit *u, skill_t sk, int n, bool(*learn)(unit *, skill_t, double))
+{
+    if (n != 0 && (is_monsters(u->faction) || playerrace(u_race(u)))) {
+        double chance = produceexp_chance();
+        if (chance > 0.0F) {
+            learn(u, sk, (n * chance) / u->number);
+        }
+    }
+}
+
+void produceexp(struct unit *u, skill_t sk, int n)
+{
+    produceexp_ex(u, sk, n, learn_skill);
+}
diff --git a/src/study.h b/src/study.h
index 1feb55921..859080b60 100644
--- a/src/study.h
+++ b/src/study.h
@@ -26,13 +26,15 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
-    extern int teach_cmd(struct unit *u, struct order *ord);
-    extern int study_cmd(struct unit *u, struct order *ord);
+    int teach_cmd(struct unit *u, struct order *ord);
+    int study_cmd(struct unit *u, struct order *ord);
 
-    extern magic_t getmagicskill(const struct locale *lang);
-    extern bool is_migrant(struct unit *u);
-    extern int study_cost(struct unit *u, skill_t talent);
+    magic_t getmagicskill(const struct locale *lang);
+    bool is_migrant(struct unit *u);
+    int study_cost(struct unit *u, skill_t talent);
 
+    void produceexp(struct unit *u, skill_t sk, int n);
+    void produceexp_ex(struct unit *u, skill_t sk, int n, bool(*learn)(struct unit *, skill_t, double));
 #define MAXTEACHERS 20
     typedef struct teaching_info {
         struct unit *teachers[MAXTEACHERS];
diff --git a/src/study.test.c b/src/study.test.c
index babfc8859..e79a35412 100644
--- a/src/study.test.c
+++ b/src/study.test.c
@@ -136,12 +136,39 @@ static void test_study_bug_2194(CuTest *tc) {
     test_cleanup();
 }
 
+static CuTest *g_tc;
+
+static bool cb_learn_one(unit *u, skill_t sk, double chance) {
+    CuAssertIntEquals(g_tc, SK_ALCHEMY, sk);
+    CuAssertDblEquals(g_tc, 0.5 / u->number, chance, 0.01);
+    return false;
+}
+
+static bool cb_learn_two(unit *u, skill_t sk, double chance) {
+    CuAssertIntEquals(g_tc, SK_ALCHEMY, sk);
+    CuAssertDblEquals(g_tc, 2 * 0.5 / u->number, chance, 0.01);
+    return false;
+}
+
+static void test_produceexp(CuTest *tc) {
+    unit *u;
+
+    g_tc = tc;
+    test_cleanup();
+    u = test_create_unit(test_create_faction(0), test_create_region(0, 0, 0));
+    config_set("study.from_use", "0.5");
+    produceexp_ex(u, SK_ALCHEMY, 1, cb_learn_one);
+    produceexp_ex(u, SK_ALCHEMY, 2, cb_learn_two);
+    test_cleanup();
+}
+
 CuSuite *get_study_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
     SUITE_ADD_TEST(suite, test_study_no_teacher);
     SUITE_ADD_TEST(suite, test_study_with_teacher);
     SUITE_ADD_TEST(suite, test_study_with_bad_teacher);
+    SUITE_ADD_TEST(suite, test_produceexp);
     DISABLE_TEST(suite, test_study_bug_2194);
     return suite;
 }