Update README.md

Author: JeffreySarnoff

README.md

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 For multiprecision numerical computing using values with 25..2,500 digits. With arithmetic and higher level mathematics, this package offers you the best balance of performance and accuracy.
 
-This package uses the [Arb C Library](http://arblib.org/index.html), and adapts some C library interface work from [Nemo](https://github.com/wbhart/Nemo.jl) (see [_below_](https://github.com/JeffreySarnoff/ArbNumerics.jl/blob/master/README.md#acknowledgements)).
+This package uses the [Arb C Library](http://arblib.org/index.html), and adapts some C library interface work from [Nemo](https://github.com/wbhart/Nemo.jl) (see [_below_](https://github.com/JeffreySarnoff/ArbNumerics.jl/blob/master/README.md#acknowledgements)). Here is a presentation by the designer and architect of the [Arb C library](https://fredrikj.net/math/oxford2019.pdf).
 
 
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