diff --git a/src/CactusSmilesConverter.php b/src/CactusSmilesConverter.php
index 44052e3..496e07b 100644
--- a/src/CactusSmilesConverter.php
+++ b/src/CactusSmilesConverter.php
@@ -15,7 +15,8 @@ use \GuzzleHttp\Client;
 class CactusSmilesConverter extends SmilesConverter
 {
     /**
-     * Initializes a new instance of a conversion service between compound names and SMILES strings.
+     * Initializes a new instance of a conversion service between compound names and SMILES strings that uses a
+     * dedicated lookup service.
      *
      * @param Database $db              the database in which to cache lookup results
      * @param SmilesConverter $fallback the conversion service to fall back to in case of error
diff --git a/src/WikipediaSmilesConverter.php b/src/WikipediaSmilesConverter.php
index 154e3b4..46595e1 100644
--- a/src/WikipediaSmilesConverter.php
+++ b/src/WikipediaSmilesConverter.php
@@ -16,7 +16,8 @@ use pQuery;
 class WikipediaSmilesConverter extends SmilesConverter
 {
     /**
-     * Initializes a new instance of a conversion service between compound names and SMILES strings.
+     * Initializes a new instance of a conversion service between compound names and SMILES strings that scrapes SMILES
+     * strings from Wikipedia.
      *
      * @param Database $db              the database in which to cache lookup results
      * @param SmilesConverter $fallback the conversion service to fall back to in case of error