It displays nicely done equations in a .pdf or .epub fine:
http://people.umass.edu/klement/russell-imp.html
The problem arises when one doesn't have access to the source and is displaying a bitmap of a size which doesn't map to the display well and has to use the scaling features.
The .pdfs in question look to be letter-sized and would display well enough in landscape format, half a page at a time, depending on your tolerance for small type at a not very high resolution --- to test this take a screen grab of a page, size it to ~4.875" wide, downsample it to 800 pixels wide, then print that out and see how readable you consider it to be.
William