ERIC is a great resource. It contains citations and links to published journal articles, and to informally published or self-archived work. If the item has an EJ accession number and doesn’t have a DOI treat it like a journal in print.
If there is an ED accession number in the item’s record add Retrieved from ERIC database. (ED******) to the end of the citation with the ED number.
Informally Published, or Self-Archived Work
Kubota, K. (2007). “Soaking” models for learning: Analyzing Japanese learning/teaching process from a socio-historical perspective. Retrieved from ERIC database. (ED498566)
Alonzo, J., Gonzalez, M., & Tindal, G. (2013). The development of easyCBM Spanish literacy assessments for use in grades K-2 (Technical Report #1301). Eugene, OR: University of Oregon, Behavioral Research and Teaching (BRT). Retrieved from ERIC database. (ED545273)
(American Psychological Association, 2010, p. 212 )