1
by Kent R. Kerley
Published 2015
MDPI AG - Multidisciplinary Digital Publishing Institute

2
by Patricia A. Watson
Published 1991
Newfound Press

4
by René Hefti
Published 2018
MDPI AG - Multidisciplinary Digital Publishing Institute

5
by Wineburg, Robert
Published 2019
MDPI - Multidisciplinary Digital Publishing Institute

6
by Büssing, Arndt
Published 2019
MDPI - Multidisciplinary Digital Publishing Institute