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One often reads that there are (at least) 43 special points on the nine point circle of triangle geometry. Can anybody give me a reference which contains an explicit description of them (preferably accessible i.e. on internet or in a good---but not great---university library)?

with thanks

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What exactly do you mean by a special point? Are you looking for points which divide segment in a ratio, or point of concurrence,intersection of some lines or something else. – sabertooth Jul 7 '12 at 18:21
see the Weisstein page about the Nine-Point Circle and the link after (3) to the indices of the Kimberling centers as proposed by Joseph. – Raymond Manzoni Jul 7 '12 at 20:47
@Raymond: thanks, just what i was looking for, jbc – jbc Jul 8 '12 at 9:33
@jbc: you are welcome! – Raymond Manzoni Jul 8 '12 at 9:50

You might look at some of what is on Clark Kimmerling's web page:

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