article by Friedrich Wilhelm Graf published in Merkur (2015), Heft: 792, pp. 4-17.

article by Friedrich Wilhelm Graf published in Merkur (2015), Heft: 798, pp. 49-56.

article by Friedrich Wilhelm Graf published in Merkur (2014), issue 786, pp. 1000-1009.

article by Friedrich Wilhelm Graf published in Merkur (2014), issue 780, pp. 436-442.

article by Friedrich Wilhelm Graf published in Merkur (2016), Heft: 804, pp. 53-62.

article by Friedrich Wilhelm Graf published in Merkur (2016), Heft: 810, pp. 49-56.

article by Friedrich Wilhelm Graf published in Merkur (2019), no. 845, pp. 5-14.

book edition published in 2019