diff --git a/composer.json b/composer.json
index 0abc08b..78cb39b 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,8 @@
         }
     ],
     "require": {
-        "php": "^7.0"
+        "php": "^7.0",
+        "psr/http-message": "^1.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/ClientInterface.php b/src/ClientInterface.php
index 253c986..d29ef79 100644
--- a/src/ClientInterface.php
+++ b/src/ClientInterface.php
@@ -10,7 +10,7 @@ interface ClientInterface
     /**
      * Sends a PSR-7 request and returns a PSR-7 response.
      *
-     * Every technically correct HTTP response MUST be returned as is, even if it represents an HTTP
+     * Every technically correct HTTP response MUST be returned as is, even if it represents a HTTP
      * error response or a redirect instruction. The only special case is 1xx responses, which MUST
      * be assembled in the HTTP client.
      *
@@ -25,7 +25,7 @@ interface ClientInterface
      *
      * @return ResponseInterface
      *
-     * @throws \Psr\Http\Client\Exception If an error happens during processing the request.
+     * @throws \Psr\Http\Client\ClientException If an error happens during processing the request.
      */
     public function sendRequest(RequestInterface $request): ResponseInterface;
 }
diff --git a/src/Exception/RequestException.php b/src/Exception/RequestException.php
index bddf16b..4c392bd 100644
--- a/src/Exception/RequestException.php
+++ b/src/Exception/RequestException.php
@@ -2,15 +2,15 @@
 
 namespace Psr\Http\Client\Exception;
 
-use Psr\Http\Message\RequestInterface;
 use Psr\Http\Client\ClientException;
+use Psr\Http\Message\RequestInterface;
 
 /**
  * Exception for when a request failed.
  *
  * Examples:
- *      - Request is invalid (eg. method is missing)
- *      - Runtime request errors (like the body stream is not seekable)
+ *      - Request is invalid (e.g. method is missing)
+ *      - Runtime request errors (e.g. the body stream is not seekable)
  */
 interface RequestException extends ClientException
 {