diff --git a/math/readme.md b/math/readme.md
index 2c78fa24..d9ecb310 100644
--- a/math/readme.md
+++ b/math/readme.md
@@ -7,6 +7,7 @@
 - [BPM/workflow/math](https://github.com/bpmbpm/doc/tree/main/BPM/workflow/math)
 - [Математика креативности](https://habr.com/ru/articles/946764/)
 - Теория связей https://github.com/bpmbpm/doc/tree/main/METAMODEL/LINK
+- https://github.com/bpmbpm/doc/tree/main/METAMODEL
 ### formalism
 #### Isabelle
 - [wiki](https://ru.wikipedia.org/wiki/Isabelle#:~:text=Isabelle%20%E2%80%94%20%D0%B8%D0%BD%D1%82%D0%B5%D1%80%D0%B0%D0%BA%D1%82%D0%B8%D0%B2%D0%BD%D1%8B%D0%B9%20%D0%B8%D0%BD%D1%81%D1%82%D1%80%D1%83%D0%BC%D0%B5%D0%BD%D1%82%20%D0%B4%D0%BB%D1%8F%20%D0%B0%D0%B2%D1%82%D0%BE%D0%BC%D0%B0%D1%82%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%BE%D0%B3%D0%BE,%D0%BD%D0%B0%D0%BF%D0%B8%D1%81%D0%B0%D0%BD%20%D0%BD%D0%B0%20%D1%8F%D0%B7%D1%8B%D0%BA%D0%B5%20Standard%20ML.) серьёзные разработки в области теории множеств проводились с использованием Isabelle/ZF.