The Cyclicity of a Class of Global Nilpotent Center Under Perturbations of Piecewise Smooth Polynomials with Four $$\hbox {Zones}^*$$ Zones ∗ | SpringerLink
Beweis ∑k=1 bis n 1/(k*(k+1) = n/(n+1) | Mathelounge
Bessel Function of the First Kind -- from Wolfram MathWorld
Mathematical induction - Wikipedia
Cooker hob KE Induction, Induction Hobs
Vollständige Induktion, Summenformel für Kubikzahlen | Mathelounge
Induction cooktop - BRAHMA K - BARBECOOK - 2 burner / floor-standing / with front controls