https://www.scirp.org/reference/ReferencesPapers?ReferenceID=1869079
Johnson, R.B. and Onwuegbuzie, J.A. (2004) Mixed Methods Research A Research Paradigm Whose Time...
Johnson, R.B. and Onwuegbuzie, J.A. (2004) Mixed Methods Research A Research Paradigm Whose Time Has Come. Educational Researcher, 33, 14-26.