Unleashing the Power of Brushes | Real World Adobe Illustrator CS5: Creative Drawing | Peachpit
Working with Brushes - Adobe Illustrator CC - page 483
cs6 - Illustrator: Getting the error message 'The selected artwork contains an element that cannot be used in a pattern brush' - Graphic Design Stack Exchange
Unleashing the Power of Brushes | Real World Adobe Illustrator CS5: Creative Drawing | Peachpit
How to Make, Use, and Manipulate a Bristle Brush in Adobe Illustrator | Envato Tuts+
Unleashing the Power of Brushes | Real World Adobe Illustrator CS5: Creative Drawing | Peachpit
I accidentally drew with the freehand path tool instead of the brush tool for some of my linework and I think it's a huge improvement : r/krita