diff --git a/README.md b/README.md
index 8fc4224..d820da6 100644
--- a/README.md
+++ b/README.md
@@ -23,10 +23,11 @@ Normally a web application is using following pattern to modify data in the data
 1. **Load resource** from database. **Resource** is some portion of data 
 such as set of records from relational database, document from Document-oriented database or value from KV store
 (in Domain-Driven Design terms it is called an [aggregate](https://martinfowler.com/bliki/DDD_Aggregate.html)).
-Lock the entire resource pessimistically or optimistically (by reading version number).
+Lock the entire resource [optimistically](https://www.martinfowler.com/eaaCatalog/optimisticOfflineLock.html) 
+by reading version number.
 2. **Apply change** to data in plain Go
-3. **Save resource** to database. Release the pessimistic lock. Or run
-atomic update with version check (optimistic lock).
+3. **Save resource** to database. Release the lock by running
+atomic update with version check.
 
 But such architecture does not scale well if the number of requests 
 for a single resource is very high
@@ -68,7 +69,7 @@ err := processor.Run(ctx, resourceKey, func(r *YourResource) {
 })
 ```
 
-For real-life example see [example web application](https://github.com/elgopher/batch-example).
+**For real-life example see [example web application](https://github.com/elgopher/batch-example).**
 
 ## Installation
 
diff --git a/go.mod b/go.mod
index 4a3085f..04e445f 100644
--- a/go.mod
+++ b/go.mod
@@ -2,10 +2,10 @@ module github.com/elgopher/batch
 
 go 1.18
 
+require github.com/stretchr/testify v1.7.0
+
 require (
 	github.com/davecgh/go-spew v1.1.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/stretchr/objx v0.1.0 // indirect
-	github.com/stretchr/testify v1.7.0 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
 )
diff --git a/go.sum b/go.sum
index 7b4dc41..acb88a4 100644
--- a/go.sum
+++ b/go.sum
@@ -2,10 +2,10 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=