It's definitely a badly drawn schematic, but by painfully staring at it long enough I see the circuit. Both the (vertical) 51r's are next to LM334 current sources on the outputs of the 5532's, for forced class A operation, as the link in post #2 explains.
The second 5532 within the feedback loop does appear to be for the purpose described in Analog's AN107 app note. The LF411 is of course a servo to zero the output offset.
The link in post #3 is broken. The correct and unmutilated URL for the Analog Devices AN107 is (right click and copy the LINK, not the text!):
ftp://ftp.analog.com/pub/www/library/applicationNotes/instrumentation/AN107.pdf
The second 5532 within the feedback loop does appear to be for the purpose described in Analog's AN107 app note. The LF411 is of course a servo to zero the output offset.
The link in post #3 is broken. The correct and unmutilated URL for the Analog Devices AN107 is (right click and copy the LINK, not the text!):
ftp://ftp.analog.com/pub/www/library/applicationNotes/instrumentation/AN107.pdf
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