As far as citing a Lumen text using APA or MLA, it can be a bit tricky because we don't have one author per se. We have several writers and contributors who have been involved in the creation and curation of our textbooks. We suggest you use the citation process for the an eBook with the author listed as Lumen Learning. You can use this page from the APA website as a reference point and this page from the OWL Purdue website as your MLA reference point. you'll want to list the current year since we are constantly updating our texts.
Citation practices have not really caught up with OER, so we try to make use of the best current practice listed by APA, MLA, Chicago, etc. This is a challenge of the OER "publication" model.
Here's what we advise, we've provided details below using our Psychology course as an example:
APA
Lumen Learning (2020). Introduction to Psychology. Retrieved from https://courses.
MLA
Introduction to Psychology. Lumen Learning, 2020 https://courses.lumenlearning.