ir. H.C. Theisens 
Lean Six Sigma Yellow Belt – English version [PDF ebook] 
Mindset, Skill set and Tool set

This book is intended for those who want to get started with carrying out improvement projects on the shop floor or in their own work environment. In addition, this book is intended for anyone who participates as a team member in a larger Lean or Six Sigma, Green or Black Belt project.
In terms of structure, this book follows the LSSA syllabus for Lean Six Sigma Yellow Belt. All techniques mentioned in this syllabus are covered in this book. It is advised to also use the accompanying exercise book.