@article{com.arsdigita.cms.contenttypes.SciMember-id-106330012020, author = "Michael Gessler and Christine Siemer", journal = "International Journal for Research in Vocational Education and Training", number = "1", pages = "91 - 125", title = "Umbrella review: Methodological review of reviews published in peer-reviewed journals with a substantial focus on vocational education and training research", volume = "7", year = "2020"}