Sources

Source

http://www.physicsoftheuniverse.com/scientists_planck.html

http://www.esa.int/Our_Activities/Space_Science/Planck/Max_Planck_Originator_of_quantum_theory

http://www.zephyrus.co.uk/maxplanck.html

http://www.softschools.com/facts/scientists/max_planck_facts/1723/