diff --git a/README.md b/README.md
index f8b4f8c..31d64ff 100644
--- a/README.md
+++ b/README.md
@@ -140,7 +140,7 @@ python roentgen.py -b 2.284,48.86,2.29,48.865
 
 #### Required ####
 
-  * `--boundary-box` or `-b`: boundary box to draw. Value: `<longitude 1>,<latitude 1>,<longitude 2>,<latitude 2>`. Use space before first `-` to escape negative values.
+  * `--boundary-box` or `-b`: boundary box to draw. Value: `<longitude 1>,<latitude 1>,<longitude 2>,<latitude 2>`. If first value is negative, use quotation marks and space before first `-`. For example, `-b " -122.335,47.614,-122.325,47.617"`.
 
 #### Optional ####
 
@@ -164,7 +164,7 @@ Tile will be stored as SVG file to `tiles/tile_<zoom level>_<x>_<y>.svg`, where
 Example:
 
 ```bash
-python3 roentgen.py tile -c 55.7510637,37.6270761 -s 18
+python roentgen.py tile -c 55.7510637,37.6270761 -s 18
 ```
 
 will generate SVG file `tiles/tile_18_158471_81953.svg`.
diff --git a/doc/readme.moi b/doc/readme.moi
index 0112aed..79ef12d 100644
--- a/doc/readme.moi
+++ b/doc/readme.moi
@@ -183,7 +183,7 @@ Example\:
 \4 {Required} {required_arguments}
 
 \list
-    {\tt {--boundary-box} or \tt {-b}\: boundary box to draw. Value\: \tt {<longitude 1>,<latitude 1>,<longitude 2>,<latitude 2>}.  Use space before first \tt {-} to escape negative values.}
+    {\tt {--boundary-box} or \tt {-b}\: boundary box to draw. Value\: \tt {<longitude 1>,<latitude 1>,<longitude 2>,<latitude 2>}.  If first longitude is negative, use quotation marks and space before first \tt {-}.  For example, \tt {-b " -122.335,47.614,-122.325,47.617"}.}
 
 \4 {Optional} {optional_arguments}
 
@@ -204,6 +204,6 @@ Tile will be stored as SVG file to \tt {tiles/tile_<zoom level>_<x>_<y>.svg}, wh
 
 Example\:
 
-\code {python3 roentgen.py tile -c 55.7510637,37.6270761 -s 18} {bash}
+\code {python roentgen.py tile -c 55.7510637,37.6270761 -s 18} {bash}
 
-will generate SVG file \tt {tiles/tile_18_158471_81953.svg}.
\ No newline at end of file
+will generate SVG file \tt {tiles/tile_18_158471_81953.svg}.