In December 2018, “The Space Physics Environment Data Analysis System (SPEDAS)” was accepted for publication in Space Science Reviews.

If you benefit from SPEDAS code, please consider citing this paper. You can simply add the citation in your acknowledgment, and that could include your software version. For example: “Data access and processing was done using SPEDAS V3.1, see Angelopoulos et al., 2019” and that would be natural and informative for readers.