Smolka, Josef: Michael Mästlin and Galileo Galilei. (German Title: Michael Mästlin und Galileo Galilei) , 2002 Verlag Harri Deutsch, Frankfurt am Main, In the earlier literature it is incorrectly claimed that Mästlin, when travelling through Italy, converted Galilei to copernicanism. We know today that Galilei was first introduced to Copernicus' work through Christian Wursteisen.Adsabs.harvard.edu
J J O'Connor and E F Robertson, The Golden ratio, 2001, The first known calculation of the golden ratio as a decimal was given in a letter written in 1597 by Michael Maestlin, at the University of Tübingen, to his former student Kepler. He gives "about 0.6180340" for the length of the longer segment of a line of length 1 divided in the golden ratio. The correct value is 0.61803398874989484821... The mystical feeling for the golden ratio was of course attractive to Kepler, as was its relation to the regular solids.History.mcs.st-andrews.ac.uk
