Riehle, Dirk.«Paid vs. Volunteer Work in Open Source». A: 2014 47th Hawaii International Conference on System Sciences. IEEE,2014,p.3286–3295. DOI10.1109/HICSS.2014.407. ISBN 978-1-4799-2504-9.
Riehle, Dirk.«Paid vs. Volunteer Work in Open Source». A: 2014 47th Hawaii International Conference on System Sciences. IEEE,2014,p.3286–3295. DOI10.1109/HICSS.2014.407. ISBN 978-1-4799-2504-9.