When googling for a Professional Sorority that no longer exists ("Epsilon Eta Phi") I got a hit at the Federal Trade Commission that I found absolutely fascinating. A full Federal Trade Commission case filed in 1961 and decided in 1968 that ultimately caused Balfour to spin off Burr, Patterson & Auld.
The first half of the case starts on page 345 of
https://www.ftc.gov/system/files/doc...4pg324-424.pdf and the rest of the case is at
https://www.ftc.gov/system/files/doc...4pg425-536.pdf
There are lots of interesting things here, including a *lot* of skullduggery by Balfour including not informing the Fraternity and Sorority community that they had bought BPA. Statements from members of Fraternity and Sorority Leadership are there as well as tables containing which supplier (Balfour, BPA or other) each fraternity or sorority used in the 1960s, size of each greek letter organization in chapters and brothers/sisters and lots of other things.
I found it fascinating!