Update README.md

README.md

@@ -27,7 +27,7 @@ A constructed BVH can be used to quickly intersect a ray with the geometry, usin
 The constructed BVH will have a layout suitable for construction ('````WALD_32BYTE````'). Several other layouts for the same data are available, which all serve one or more specific purposes. You can convert between layouts using ````BVH::Convert````. The available layouts are:
 * ````BVH::WALD_32BYTE```` : A compact format that stores the AABB for a node, along with child pointers and leaf information in a cross-platform-friendly way. The 32-byte size allows for cache-line alignment.
 * ````BVH::VERBOSE```` : A format designed for modifying BVHs, e.g. for post-build optimizations using ````BVH::Optimize()````.
-* ````BVH::AILA_LAINE```` : This format uses 64 bytes per node and stores the AABBs of the two child nodes. This is the format recommended for basic GPU ray tracing.
+* ````BVH::AILA_LAINE```` : This format uses 64 bytes per node and stores the AABBs of the two child nodes. This is the format presented in the [2009 Aila & Laine paper](https://research.nvidia.com/sites/default/files/pubs/2009-08_Understanding-the-Efficiency/aila2009hpg_paper.pdf) and recommended for basic GPU ray tracing.
 * ````BVH::BASIC_BVH4```` : In this format, each node stores four child pointers, reducing the depth of the tree. This improves performance for divergent rays. Based on the [2008 paper](https://graphics.stanford.edu/~boulos/papers/multi_rt08.pdf) by Ingo Wald et al.
 * ````BVH::BVH4_GPU```` : The ````BASIC_BVH4```` format can be converted to the more compact ````BVH4_GPU```` layout, which will be faster for GPU ray tracing.
 * ````BVH::BASIC_BVH8```` : This format stores eight child pointers, further reducing the depth of the tree. The only purpose is the construction of ````BVH::CWBVH````.