If you share a love of Garry Winogrand’s work (see this blog posting and this photo.net book review), you’ll probably enjoy seeing the work of his Chicago-based doppelganger: Vivian Maier (1926-2009). See her online portfolios, for example, and this three-minute BBC video.
[Separately, it seems odd that the folks trying to make money out of this woman’s work by selling prints are doing them in a 16×20-inch size (link). A lot of street photography seems to work better if printed smaller, especially if originated with a 35mm film camera.]
They just released a documentary about her called Finding Vivian Maier. It’s well worth seeking out.
In the link that you give above, they show some of Vivian’s negatives that appear to be shot in medium format (120 film = 60mm x 60mm square negatives).
http://vivianmaier.maloofcollection.netdna-cdn.com/wp-content/uploads/2013/10/Vivian_Maier_Negatives_Light_Table.jpg