diff --git a/package-lock.json b/package-lock.json
index a629d5d50..18c1ac85a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -32719,7 +32719,7 @@
     },
     "packages/core": {
       "name": "@openscd/core",
-      "version": "0.1.2",
+      "version": "0.1.3",
       "license": "Apache-2.0",
       "dependencies": {
         "@lit/localize": "^0.11.4",
diff --git a/packages/core/foundation.ts b/packages/core/foundation.ts
index c7cd164a4..60b3a30ad 100644
--- a/packages/core/foundation.ts
+++ b/packages/core/foundation.ts
@@ -34,3 +34,11 @@ export type {
   EditCompletedEvent,
   EditCompletedDetail,
 } from './foundation/edit-completed-event.js';
+
+/** @returns the cartesian product of `arrays` */
+export function crossProduct<T>(...arrays: T[][]): T[][] {
+  return arrays.reduce<T[][]>(
+    (a, b) => <T[][]>a.flatMap(d => b.map(e => [d, e].flat())),
+    [[]]
+  );
+}
diff --git a/packages/core/foundation/scl.ts b/packages/core/foundation/scl.ts
new file mode 100644
index 000000000..966d47ead
--- /dev/null
+++ b/packages/core/foundation/scl.ts
@@ -0,0 +1,89 @@
+import { crossProduct } from '../foundation.js';
+
+function getDataModelChildren(parent: Element): Element[] {
+  if (['LDevice', 'Server'].includes(parent.tagName))
+    return Array.from(parent.children).filter(
+      child =>
+        child.tagName === 'LDevice' ||
+        child.tagName === 'LN0' ||
+        child.tagName === 'LN'
+    );
+
+  const id =
+    parent.tagName === 'LN' || parent.tagName === 'LN0'
+      ? parent.getAttribute('lnType')
+      : parent.getAttribute('type');
+
+  return Array.from(
+    parent.ownerDocument.querySelectorAll(
+      `LNodeType[id="${id}"] > DO, DOType[id="${id}"] > SDO, DOType[id="${id}"] > DA, DAType[id="${id}"] > BDA`
+    )
+  );
+}
+
+export function existFcdaReference(fcda: Element, ied: Element): boolean {
+  const [ldInst, prefix, lnClass, lnInst, doName, daName, fc] = [
+    'ldInst',
+    'prefix',
+    'lnClass',
+    'lnInst',
+    'doName',
+    'daName',
+    'fc',
+  ].map(attr => fcda.getAttribute(attr));
+
+  const sinkLdInst = ied.querySelector(`LDevice[inst="${ldInst}"]`);
+  if (!sinkLdInst) return false;
+
+  const prefixSelctors = prefix
+    ? [`[prefix="${prefix}"]`]
+    : ['[prefix=""]', ':not([prefix])'];
+  const lnInstSelectors = lnInst
+    ? [`[inst="${lnInst}"]`]
+    : ['[inst=""]', ':not([inst])'];
+
+  const anyLnSelector = crossProduct(
+    ['LN0', 'LN'],
+    prefixSelctors,
+    [`[lnClass="${lnClass}"]`],
+    lnInstSelectors
+  )
+    .map(strings => strings.join(''))
+    .join(',');
+
+  const sinkAnyLn = ied.querySelector(anyLnSelector);
+  if (!sinkAnyLn) return false;
+
+  const doNames = doName?.split('.');
+  if (!doNames) return false;
+
+  let parent: Element | undefined = sinkAnyLn;
+  for (const doNameAttr of doNames) {
+    parent = getDataModelChildren(parent).find(
+      child => child.getAttribute('name') === doNameAttr
+    );
+    if (!parent) return false;
+  }
+
+  const daNames = daName?.split('.');
+  const someFcInSink = getDataModelChildren(parent).some(
+    da => da.getAttribute('fc') === fc
+  );
+  if (!daNames && someFcInSink) return true;
+  if (!daNames) return false;
+
+  let sinkFc = '';
+  for (const daNameAttr of daNames) {
+    parent = getDataModelChildren(parent).find(
+      child => child.getAttribute('name') === daNameAttr
+    );
+
+    if (parent?.getAttribute('fc')) sinkFc = parent.getAttribute('fc')!;
+
+    if (!parent) return false;
+  }
+
+  if (sinkFc !== fc) return false;
+
+  return true;
+}
diff --git a/packages/core/package.json b/packages/core/package.json
index 4d6cbe777..5fe733aab 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -13,6 +13,7 @@
   ],
   "exports": {
     ".": "./dist/foundation.js",
+    "./foundation/scl.js": "./dist/foundation/scl.js",
     "./foundation/deprecated/editor.js": "./dist/foundation/deprecated/editor.js",
     "./foundation/deprecated/open-event.js": "./dist/foundation/deprecated/open-event.js",
     "./foundation/deprecated/settings.js": "./dist/foundation/deprecated/settings.js",
@@ -159,4 +160,4 @@
       "prettier --write"
     ]
   }
-}
+}
\ No newline at end of file