diff --git a/api/__init__.py b/api/__init__.py
index ed476a0..9b808e0 100644
--- a/api/__init__.py
+++ b/api/__init__.py
@@ -62,6 +62,9 @@ from .s16_emitters import get_emitter_schema, get_emitter, set_emitter
 
 from .s17_quality import get_quality_schema, get_quality, set_quality
 
+from .s18_sources import SOURCE_TYPE_CONCEN, SOURCE_TYPE_MASS, SOURCE_TYPE_FLOWPACED, SOURCE_TYPE_SETPOINT
+from .s18_sources import get_source_schema, get_source, set_source, add_source, delete_source
+
 from .s21_times import TIME_STATISTIC_NONE, TIME_STATISTIC_AVERAGED, TIME_STATISTIC_MINIMUM, TIME_STATISTIC_MAXIMUM, TIME_STATISTIC_RANGE
 from .s21_times import get_time_schema, get_time, set_time
 
diff --git a/api/s18_sources.py b/api/s18_sources.py
new file mode 100644
index 0000000..2d489c0
--- /dev/null
+++ b/api/s18_sources.py
@@ -0,0 +1,100 @@
+from .operation import *
+from .s0_base import *
+
+SOURCE_TYPE_CONCEN = 'CONCEN'
+SOURCE_TYPE_MASS = 'MASS'
+SOURCE_TYPE_FLOWPACED = 'FLOWPACED'
+SOURCE_TYPE_SETPOINT = 'SETPOINT'
+
+def get_source_schema(name: str) -> dict[str, dict[str, Any]]:
+    return { 'node'      : {'type': 'str'   , 'optional': False , 'readonly': True },
+             's_type'    : {'type': 'str'   , 'optional': False , 'readonly': False},
+             'strength'  : {'type': 'float' , 'optional': False , 'readonly': False},
+             'pattern'   : {'type': 'str'   , 'optional': True ,  'readonly': False} }
+
+
+def get_source(name: str, node: str) -> dict[str, Any]:
+    s = read(name, f"select * from sources where node = '{node}'")
+    d = {}
+    d['node'] = str(s['node'])
+    d['s_type'] = str(s['type'])
+    d['strength'] = float(s['strength'])
+    d['pattern'] = str(s['pattern']) if s['pattern'] != None else None
+    return d
+
+
+class Source(object):
+    def __init__(self, input: dict[str, Any]) -> None:
+        self.type = 'source'
+        self.node = str(input['node'])
+        self.s_type = str(input['s_type'])
+        self.strength = float(input['strength'])
+        self.pattern = str(input['pattern']) if 'pattern' in input and input['pattern'] != None else None
+
+        self.f_type = f"'{self.type}'"
+        self.f_node = f"'{self.node}'"
+        self.f_s_type = f"'{self.s_type}'"
+        self.f_strength = self.strength
+        self.f_pattern = f"'{self.pattern}'" if self.pattern != None else 'null'
+
+    def as_dict(self) -> dict[str, Any]:
+        return { 'type': self.type, 'node': self.node, 's_type': self.s_type, 'strength': self.strength, 'pattern': self.pattern }
+
+    def as_id_dict(self) -> dict[str, Any]:
+        return { 'type': self.type, 'node': self.node }
+
+
+def set_source_cache(name: str, cs: ChangeSet) -> SqlChangeSet:
+    old = Source(get_source(name, cs.operations[0]['node']))
+    raw_new = get_source(name, cs.operations[0]['node'])
+
+    new_dict = cs.operations[0]
+    schema = get_source_schema(name)
+    for key, value in schema.items():
+        if key in new_dict and not value['readonly']:
+            raw_new[key] = new_dict[key]
+    new = Source(raw_new)
+
+    redo_sql = f"update sources set type = {new.f_s_type}, strength = {new.f_strength}, pattern = {new.f_pattern} where node = {new.f_node};"
+    undo_sql = f"update sources set type = {old.f_s_type}, strength = {old.f_strength}, pattern = {old.f_pattern} where node = {old.f_node};"
+
+    redo_cs = g_update_prefix | new.as_dict()
+    undo_cs = g_update_prefix | old.as_dict()
+
+    return SqlChangeSet(redo_sql, undo_sql, redo_cs, undo_cs)
+
+
+def set_source(name: str, cs: ChangeSet) -> ChangeSet:
+    return execute_command(name, set_source_cache(name, cs))
+
+
+def add_source_cache(name: str, cs: ChangeSet) -> SqlChangeSet:
+    new = Source(cs.operations[0])
+
+    redo_sql = f"insert into sources (node, type, strength, pattern) values ({new.f_node}, {new.f_s_type}, {new.f_strength}, {new.f_pattern});"
+    undo_sql = f"delete from sources where node = {new.f_node};"
+
+    redo_cs = g_add_prefix | new.as_dict()
+    undo_cs = g_delete_prefix | new.as_id_dict()
+
+    return SqlChangeSet(redo_sql, undo_sql, redo_cs, undo_cs)
+
+
+def add_source(name: str, cs: ChangeSet) -> ChangeSet:
+    return execute_command(name, add_source_cache(name, cs))
+
+
+def delete_source_cache(name: str, cs: ChangeSet) -> SqlChangeSet:
+    old = Source(get_source(name, cs.operations[0]['node']))
+
+    redo_sql = f"delete from sources where node = {old.f_node};"
+    undo_sql = f"insert into sources (node, type, strength, pattern) values ({old.f_node}, {old.f_s_type}, {old.f_strength}, {old.f_pattern});"
+
+    redo_cs = g_delete_prefix | old.as_id_dict()
+    undo_cs = g_add_prefix | old.as_dict()
+
+    return SqlChangeSet(redo_sql, undo_sql, redo_cs, undo_cs)
+
+
+def delete_source(name: str, cs: ChangeSet) -> ChangeSet:
+    return execute_command(name, delete_source_cache(name, cs))
diff --git a/script/sql/create/18.sources.sql b/script/sql/create/18.sources.sql
index 956d61d..31d7a9b 100644
--- a/script/sql/create/18.sources.sql
+++ b/script/sql/create/18.sources.sql
@@ -7,5 +7,5 @@ create table sources
   node varchar(32) primary key references _node(id)
 , type sources_type not null
 , strength numeric not null
-, time_pattern varchar(32) references _pattern(id)
+, pattern varchar(32) references _pattern(id)
 );
diff --git a/test_tjnetwork.py b/test_tjnetwork.py
index 526aa99..bdbe242 100644
--- a/test_tjnetwork.py
+++ b/test_tjnetwork.py
@@ -2410,6 +2410,172 @@ class TestApi:
         self.leave(p)
 
 
+    # 18 source
+
+
+    def test_source(self):
+        p = 'test_source'
+        self.enter(p)
+
+        add_junction(p, ChangeSet({'id': 'j0', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+        add_pattern(p, ChangeSet({'id' : 'p0', 'factors': [1.0, 2.0, 3.0]}))
+        add_pattern(p, ChangeSet({'id' : 'p1', 'factors': [1.0, 2.0, 3.0]}))
+
+        add_source(p, ChangeSet({'node': 'j0', 's_type': SOURCE_TYPE_CONCEN, 'strength': 10.0, 'pattern': 'p0'}))
+        s = get_source(p, 'j0')
+        assert s['node'] == 'j0'
+        assert s['s_type'] == SOURCE_TYPE_CONCEN
+        assert s['strength'] == 10.0
+        assert s['pattern'] == 'p0'
+
+        set_source(p, ChangeSet({'node': 'j0', 's_type': SOURCE_TYPE_FLOWPACED}))
+        s = get_source(p, 'j0')
+        assert s['node'] == 'j0'
+        assert s['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert s['strength'] == 10.0
+        assert s['pattern'] == 'p0'
+
+        set_source(p, ChangeSet({'node': 'j0', 'strength': 20.0}))
+        s = get_source(p, 'j0')
+        assert s['node'] == 'j0'
+        assert s['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert s['strength'] == 20.0
+        assert s['pattern'] == 'p0'
+
+        set_source(p, ChangeSet({'node': 'j0', 'pattern': 'p1'}))
+        s = get_source(p, 'j0')
+        assert s['node'] == 'j0'
+        assert s['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert s['strength'] == 20.0
+        assert s['pattern'] == 'p1'
+
+        delete_source(p, ChangeSet({'node': 'j0'}))
+
+        self.leave(p)
+
+
+    def test_source_op(self):
+        p = 'test_source_op'
+        self.enter(p)
+
+        add_junction(p, ChangeSet({'id': 'j0', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+        add_pattern(p, ChangeSet({'id' : 'p0', 'factors': [1.0, 2.0, 3.0]}))
+        add_pattern(p, ChangeSet({'id' : 'p1', 'factors': [1.0, 2.0, 3.0]}))
+
+        cs = add_source(p, ChangeSet({'node': 'j0', 's_type': SOURCE_TYPE_CONCEN, 'strength': 10.0, 'pattern': 'p0'})).operations[0]
+        assert cs['operation'] == API_ADD
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_CONCEN
+        assert cs['strength'] == 10.0
+        assert cs['pattern'] == 'p0'
+
+        cs = execute_undo(p).operations[0]
+        assert cs['operation'] == API_DELETE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+
+        cs = execute_redo(p).operations[0]
+        assert cs['operation'] == API_ADD
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_CONCEN
+        assert cs['strength'] == 10.0
+        assert cs['pattern'] == 'p0'
+
+        cs = set_source(p, ChangeSet({'node': 'j0', 's_type': SOURCE_TYPE_FLOWPACED})).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 10.0
+        assert cs['pattern'] == 'p0'
+
+        cs = execute_undo(p).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_CONCEN
+        assert cs['strength'] == 10.0
+        assert cs['pattern'] == 'p0'
+
+        cs = execute_redo(p).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 10.0
+        assert cs['pattern'] == 'p0'
+
+        cs = set_source(p, ChangeSet({'node': 'j0', 'strength': 20.0})).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 20.0
+        assert cs['pattern'] == 'p0'
+
+        cs = execute_undo(p).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 10.0
+        assert cs['pattern'] == 'p0'
+
+        cs = execute_redo(p).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 20.0
+        assert cs['pattern'] == 'p0'
+
+        cs = set_source(p, ChangeSet({'node': 'j0', 'pattern': 'p1'})).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 20.0
+        assert cs['pattern'] == 'p1'
+
+        cs = execute_undo(p).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 20.0
+        assert cs['pattern'] == 'p0'
+
+        cs = execute_redo(p).operations[0]
+        assert cs['operation'] == API_UPDATE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 20.0
+        assert cs['pattern'] == 'p1'
+
+        cs = delete_source(p, ChangeSet({'node': 'j0'})).operations[0]
+        assert cs['operation'] == API_DELETE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+
+        cs = execute_undo(p).operations[0]
+        assert cs['operation'] == API_ADD
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+        assert cs['s_type'] == SOURCE_TYPE_FLOWPACED
+        assert cs['strength'] == 20.0
+        assert cs['pattern'] == 'p1'
+
+        cs = execute_redo(p).operations[0]
+        assert cs['operation'] == API_DELETE
+        assert cs['type'] == 'source'
+        assert cs['node'] == 'j0'
+
+        self.leave(p)
+
+
     # 21 time
 
 
diff --git a/tjnetwork.py b/tjnetwork.py
index 787db04..68d71f6 100644
--- a/tjnetwork.py
+++ b/tjnetwork.py
@@ -52,6 +52,11 @@ CURVE_TYPE_EFFICIENCY = api.CURVE_TYPE_EFFICIENCY
 CURVE_TYPE_VOLUME = api.CURVE_TYPE_VOLUME
 CURVE_TYPE_HEADLOSS = api.CURVE_TYPE_HEADLOSS
 
+SOURCE_TYPE_CONCEN = api.SOURCE_TYPE_CONCEN
+SOURCE_TYPE_MASS = api.SOURCE_TYPE_MASS
+SOURCE_TYPE_FLOWPACED = api.SOURCE_TYPE_FLOWPACED
+SOURCE_TYPE_SETPOINT = api.SOURCE_TYPE_SETPOINT
+
 TIME_STATISTIC_NONE = api.TIME_STATISTIC_NONE
 TIME_STATISTIC_AVERAGED = api.TIME_STATISTIC_AVERAGED
 TIME_STATISTIC_MINIMUM = api.TIME_STATISTIC_MINIMUM
@@ -517,6 +522,26 @@ def set_quality(name: str, cs: ChangeSet) -> ChangeSet:
     return api.set_quality(name, cs)
 
 
+############################################################
+# source 18.[SOURCES]
+############################################################
+
+def get_source_schema(name: str) -> dict[str, dict[str, Any]]:
+    return api.get_source_schema(name)
+
+def get_source(name: str, node: str) -> dict[str, Any]:
+    return api.get_source(name, node)
+
+def set_source(name: str, cs: ChangeSet) -> ChangeSet:
+    return api.set_source(name, cs)
+
+def add_source(name: str, cs: ChangeSet) -> ChangeSet:
+    return api.add_source(name, cs)
+
+def delete_source(name: str, cs: ChangeSet) -> ChangeSet:
+    return api.delete_source(name, cs)
+
+
 ############################################################
 # time 21.[TIMES]
 ############################################################