diff --git a/css-flexbox.md b/css-flexbox.md
index 17163943a..f0c7b2a6a 100644
--- a/css-flexbox.md
+++ b/css-flexbox.md
@@ -25,8 +25,8 @@ category: CSS
       display: flex;
       display: inline-flex;
 
-      flex-direction: row;         /* ltr - default */
-      flex-direction: row-reverse; /* rtl */
+      flex-direction: row;            /* ltr - default */
+      flex-direction: row-reverse;    /* rtl */
       flex-direction: column;         /* top-bottom */
       flex-direction: column-reverse; /* bottom-top */
 
@@ -47,6 +47,9 @@ category: CSS
       flex: 1 0 0;
       order: 1;
       flex-grow: 0;
+
+      align-self: flex-start;  /* left */
+      margin-left: auto;       /* right */
     }
 
 ## Tricks
@@ -63,6 +66,14 @@ category: CSS
       margin: auto;
     }
 
+### Vertical center (2)
+
+    .container {
+      display: flex;
+      align-items: center;     /* vertical */
+      justify-content: center; /* horizontal */
+    }
+
 ### Reordering
 
     .container > .top {
@@ -113,6 +124,11 @@ Vertically-center all items.
       align-items: center;
     }
 
+### Left and right
+
+    .menu > .left  { align-self: flex-start; }
+    .menu > .right { align-self: flex-end; }
+
 ### References
 
  * [MDN: Using CSS flexbox](https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Flexible_boxes)
diff --git a/heroku.md b/heroku.md
index 318473d9b..0f37d00ac 100644
--- a/heroku.md
+++ b/heroku.md
@@ -7,12 +7,12 @@ category: Devops
 
     heroku create sushi
 
-### `sharing` - Collaboration
+### `access` - Collaboration
 
     # Manage collaborators
-      heroku sharing                     # List
-      heroku sharing:add me@xy.com
-      heroku sharing:remove me@xy.com
+      heroku access                     # List
+      heroku access:add me@xy.com
+      heroku access:remove me@xy.com
 
     # Transfer to another owner
       heroku sharing:transfer new@owner.com
diff --git a/minitest.md b/minitest.md
index a280fc477..54e329e51 100644
--- a/minitest.md
+++ b/minitest.md
@@ -20,6 +20,7 @@ category: Ruby
 
 ### Specs (.must/.wont)
 
+    expect(x)
     .must_be :==, 0
     .must_equal b
     .must_be_close_to 2.99999
diff --git a/sass.md b/sass.md
index fe0144536..8173cd6bd 100644
--- a/sass.md
+++ b/sass.md
@@ -190,9 +190,12 @@ $i: 6;
 ## Interpolation
 
 ```scss
-$klass: 'button';
+.#{$klass} { ... }      /* Class */
+call($function-name)    /* Functions */
 
-.#{$klass} { ... }  /* same as `.button` */
+@media #{$tablet}
+font: #{$size}/#{$line-height}
+url("#{$background}.jpg")
 ```
 
 ## Lists