1. Professor and Chair in Construction Engineering Management, UAS Bremen, Neustadtswall 30, 26180 Bremen, Germany (corresponding author).
2. Professor and Chair in Economics, TU Freiberg, Lessingstr. 45, 09596 Freiberg, Germany.
3. Ph.D. Student, TU Freiberg, Lessingstr. 45, 09596 Freiberg, Germany.