J. Decius, M. Knappstein, N. Schaper, and A. Seifert, “Investigating the multidimensionality of informal learning: Validation of a short measure for whitecollar workers,”10.1002/hrdq.21461__Human Resource Development Quarterly, 2021, doi:10.1002/hrdq.21461 .

S. Hubner-Benz and M. Baum, “Entrepreneurs’ human resources development,”10.1002/hrdq.21328__Human Resource Development Quarterly, vol. 29, no. 4, pp. 357–381, 2018, doi:10.1002/hrdq.21328 .