diff --git a/pl/cross/methodologies/architecture/ddd.txt b/pl/cross/methodologies/architecture/ddd.txt
index 8fac7d361..c40b67c89 100644
--- a/pl/cross/methodologies/architecture/ddd.txt
+++ b/pl/cross/methodologies/architecture/ddd.txt
@@ -48,6 +48,14 @@ https://habr.com/ru/companies/dododev/articles/523540/
     ! need to read
 2019
 https://habr.com/ru/company/jugru/blog/440772/
+2015
+Vernon - Implementing Domain-Driven Design
+    038F4A0BDE83E4490C589BC88D07AA5B
+2014
+Evans - Domain-Driven Design
+    04D80385C9E9BCCD2E076A183B003766
+    4D7B2C691CB8C9623FF3070A0129EDA8
+    AACB14D65DA1C754E286C4DC3F86BB4F
 2009
 https://www.infoq.com/articles/ddd-contextmapping/
     ! need to read
diff --git a/pl/cross/tools/quality/test/contract/books.txt b/pl/cross/tools/quality/test/contract/books.txt
new file mode 100644
index 000000000..e57b813cb
--- /dev/null
+++ b/pl/cross/tools/quality/test/contract/books.txt
@@ -0,0 +1,3 @@
+2024
+CruzPrescott - Contract Testing in Action
+    AAD61DC60619C4E5DFC326E4250B911F
diff --git a/science/ai/free/deepsek.txt b/science/ai/free/deepsek.txt
index 6a1388669..b6fdb8fd6 100644
--- a/science/ai/free/deepsek.txt
+++ b/science/ai/free/deepsek.txt
@@ -10,6 +10,8 @@ https://deepseekcoder.github.io/
 
 2025
 https://habr.com/ru/articles/877772/
+freeCodeCamp - DeepSeek-R1 Crash Course 0:00 of 1:30:55
+    https://www.youtube.com/watch?v=_CXwZ5xyFno
 Staschuk - Local R1 of 26:01
     https://www.youtube.com/watch?v=DYlYeaI9n40
     ! 7:00 olama run deepsek-r1:8b