Does anyone know where the July 1st date came from? I've seen several different dates as to when her last performance was with the group:
June 28: I believe Mary wrote this one in Dreamgirl
Late July: Flo says she hasn't been with the group since the start of August in Jet magazine Sept. 1967.
Late June: a year later, I believe also in Jet, Flo says she left the group before they even went to Vegas and was never in the group when it was named Diana Ross and the Supremes [[although this contradicts those photos that surfaced of her celebrating her birthday).

Although July 1st is probably the most accurate, how was that exact date determined?