diff --git a/packages/core/cjsBuild.js b/packages/core/cjsBuild.js
index f4e0427..5b10a97 100644
--- a/packages/core/cjsBuild.js
+++ b/packages/core/cjsBuild.js
@@ -22,7 +22,12 @@ require("esbuild")
       : "./dist/core.cjs.development.js",
     target: "es2015",
     minify: isProd,
-    external: ["react", "rxjs", "use-sync-external-store"],
+    external: [
+      "react",
+      "rxjs",
+      "@josepot/rxjs-state",
+      "use-sync-external-store",
+    ],
     format: "cjs",
     sourcemap: true,
     plugins: [fixCjsPlugin],
diff --git a/packages/core/package.json b/packages/core/package.json
index a649f07..70e81c8 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -25,8 +25,8 @@
   ],
   "scripts": {
     "build": "yarn build:ts && yarn build:esm2017 && yarn build:esm2019 && yarn build:cjs:dev && yarn build:cjs:prod",
-    "build:esm2019": "esbuild src/index.tsx --bundle --outfile=./dist/core.es2019.mjs --target=es2019 --external:react --external:rxjs --external:use-sync-external-store --format=esm --sourcemap",
-    "build:esm2017": "esbuild src/index.tsx --bundle --outfile=./dist/core.es2017.js --target=es2017 --external:react --external:rxjs --external:use-sync-external-store --format=esm --sourcemap",
+    "build:esm2019": "esbuild src/index.tsx --bundle --outfile=./dist/core.es2019.mjs --target=es2019 --external:react --external:rxjs --external:@josepot/rxjs-state --external:use-sync-external-store --format=esm --sourcemap",
+    "build:esm2017": "esbuild src/index.tsx --bundle --outfile=./dist/core.es2017.js --target=es2017 --external:react --external:rxjs --external:@josepot/rxjs-state --external:use-sync-external-store --format=esm --sourcemap",
     "build:cjs:dev": "node cjsBuild.js",
     "build:cjs:prod": "node cjsBuild.js --prod",
     "build:ts": "tsc -p ./tsconfig-build.json --outDir ./dist --skipLibCheck --emitDeclarationOnly",