Add reference paper to the function hashing documentation.

Author: kernelmethod

docs/src/function_hashing.md

@@ -19,8 +19,10 @@ julia> hashfn(x -> 5x^3 - 2x^2 - 9x + 1)
  1
 ```
 
+LSHFunctions can hash functions in any [``L^p_{\mu}(\Omega)`` function space](https://en.wikipedia.org/wiki/Lp_space) so long as ``\Omega`` has finite volume (i.e., as long as ``\int_{\Omega} d\mu(x) < +\infty``).
+
 ## Similarity statistics in function spaces
-The LSHFunctions module currently supports the following similarity statistics for function spaces. Unless otherwise stated, all functions are assumed to be members of an [``L^p_{\mu}(\Omega)`` function space](https://en.wikipedia.org/wiki/Lp_space).
+The LSHFunctions module currently supports hashing for the following similarity statistics in function spaces.
 
 ### ``L_{\mu}^p`` distance
 

docs/src/glossary.md

@@ -25,7 +25,7 @@ In the case where ``p = 2``, there is also an [inner product](https://en.wikiped
 
 where ``\overline{g(x)}`` is the complex conjugate of ``g(x)``. A function in ``L^p_{\mu}(\Omega)`` must have the property that ``\|f\|_{L^p_{\mu}}`` is finite.
 
-*Example*: ``f(x) = x^2 - 3x + 2`` is a function in ``L^2([-1,1])`` (with ``\mu`` chosen to be [Lebesgue measure](https://en.wikipedia.org/wiki/Lebesgue_measure)) because ``\|f\|_{L^2} = \sqrt{\int_{-1}^1 \left|f(x)\right|^2 \hspace{0.15cm} dx}`` is finite. However, it is *not* a function in ``L^2([-\infty,\infty])`` because the ``\|f\|_{L^2} = \sqrt{\int_{-\infty}^{\infty} \left|f(x)\right|^2 \hspace{0.15cm} dx`` is infinite.
+*Example*: ``f(x) = x^2 - 3x + 2`` is a function in ``L^2([-1,1])`` (with ``\mu`` chosen to be [Lebesgue measure](https://en.wikipedia.org/wiki/Lebesgue_measure)) because ``\|f\|_{L^2} = \sqrt{\int_{-1}^1 \left|f(x)\right|^2 \hspace{0.15cm} dx}`` is finite. However, it is *not* a function in ``L^2([-\infty,\infty])`` because ``\|f\|_{L^2} = \sqrt{\int_{-\infty}^{\infty} \left|f(x)\right|^2 \hspace{0.15cm} dx}`` is infinite.
 
 ---
 

docs/src/lshfunction_api.md

@@ -157,3 +157,5 @@ LSHFunctions.jl provides a few common utility functions that you can use across
   true
   ```
 
+## References
+- Shand, William and Becker, Stephen. *Locality-sensitive hashing in function spaces*. [arXiv:2002.03909](https://arxiv.org/abs/2002.03909).