+ * Till Roenneberg: Wie wir ticken. Die Bedeutung der Chronobiologie für uns, ISBN-13: 978-3832161880 (or in English: Internal Time. Chronotypes, Social Jet Lag and Why You're So Tired, ISBN-13: 978-0674065857)
+ * Gamma, Helm, Johnson, Vlissides: Design Patterns. Elements of Reusable Object-Oriented Software. Addison-Wesley 1994, ISBN-13 978-0201633610