diff --git a/src/mlpack/methods/ann/layer/alpha_dropout.hpp b/src/mlpack/methods/ann/layer/alpha_dropout.hpp
index 3903c7ebd6..2713bf3c78 100644
--- a/src/mlpack/methods/ann/layer/alpha_dropout.hpp
+++ b/src/mlpack/methods/ann/layer/alpha_dropout.hpp
@@ -35,7 +35,8 @@ namespace ann /** Artificial Neural Network. */ {
  *              Andreas Mayr},
  *   title   = {Self-Normalizing Neural Networks},
  *   journal = {Advances in Neural Information Processing Systems},
- *   year    = {2017}
+ *   year    = {2017},
+ *   url     = {https://arxiv.org/abs/1706.02515}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/c_relu.hpp b/src/mlpack/methods/ann/layer/c_relu.hpp
index b9812bb4c0..ea52cb999a 100644
--- a/src/mlpack/methods/ann/layer/c_relu.hpp
+++ b/src/mlpack/methods/ann/layer/c_relu.hpp
@@ -33,7 +33,8 @@ namespace ann /** Artificial Neural Network. */ {
  *   title  = {Understanding and Improving Convolutional Neural Networks
  *             via Concatenated Rectified Linear Units},
  *   author = {LWenling Shang, Kihyuk Sohn, Diogo Almeida, Honglak Lee},
- *   year   = {2016}
+ *   year   = {2016},
+ *   url    = {https://arxiv.org/abs/1603.05201}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/dropconnect.hpp b/src/mlpack/methods/ann/layer/dropconnect.hpp
index 2e0b446435..3d73896eab 100644
--- a/src/mlpack/methods/ann/layer/dropconnect.hpp
+++ b/src/mlpack/methods/ann/layer/dropconnect.hpp
@@ -46,7 +46,8 @@ namespace ann /** Artificial Neural Network. */ {
  *                Learning(ICML - 13)},
  *   author = {Li Wan and Matthew Zeiler and Sixin Zhang and Yann L. Cun and
  *             Rob Fergus},
- *   year = {2013}
+ *   year = {2013},
+ *   url  = {http://proceedings.mlr.press/v28/wan13.pdf}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/dropout.hpp b/src/mlpack/methods/ann/layer/dropout.hpp
index 358239a7c2..ade2bfa7ab 100644
--- a/src/mlpack/methods/ann/layer/dropout.hpp
+++ b/src/mlpack/methods/ann/layer/dropout.hpp
@@ -39,6 +39,7 @@ namespace ann /** Artificial Neural Network. */ {
  *   journal = {CoRR},
  *   volume  = {abs/1207.0580},
  *   year    = {2012},
+ *   url     = {https://arxiv.org/abs/1207.0580}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/elu.hpp b/src/mlpack/methods/ann/layer/elu.hpp
index 91375d59af..43d6105c82 100644
--- a/src/mlpack/methods/ann/layer/elu.hpp
+++ b/src/mlpack/methods/ann/layer/elu.hpp
@@ -56,7 +56,8 @@ namespace ann /** Artificial Neural Network. */ {
  *   title   = {Fast and Accurate Deep Network Learning by Exponential Linear
  *              Units (ELUs)},
  *   journal = {CoRR},
- *   year    = {2015}
+ *   year    = {2015},
+ *   url     = {https://arxiv.org/abs/1511.07289}
  * }
  * @endcode
  *
@@ -86,7 +87,8 @@ namespace ann /** Artificial Neural Network. */ {
  *              Andreas Mayr},
  *   title   = {Self-Normalizing Neural Networks},
  *   journal = {Advances in Neural Information Processing Systems},
- *   year    = {2017}
+ *   year    = {2017},
+ *   url = {https://arxiv.org/abs/1706.02515}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/fast_lstm.hpp b/src/mlpack/methods/ann/layer/fast_lstm.hpp
index ef20aaa145..4d25487641 100644
--- a/src/mlpack/methods/ann/layer/fast_lstm.hpp
+++ b/src/mlpack/methods/ann/layer/fast_lstm.hpp
@@ -47,7 +47,8 @@ namespace ann /** Artificial Neural Network. */ {
  *   author  = {Hochreiter, Sepp and Schmidhuber, J\"{u}rgen},
  *   title   = {Long Short-term Memory},
  *   journal = {Neural Comput.},
- *   year    = {1997}
+ *   year    = {1997},
+ *   url     = {https://www.bioinf.jku.at/publications/older/2604.pdf}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/glimpse.hpp b/src/mlpack/methods/ann/layer/glimpse.hpp
index 1c25d25e63..ed1017284d 100644
--- a/src/mlpack/methods/ann/layer/glimpse.hpp
+++ b/src/mlpack/methods/ann/layer/glimpse.hpp
@@ -15,6 +15,7 @@
  *   journal = {CoRR},
  *   volume  = {abs/1406.6247},
  *   year    = {2014},
+ *   url     = {https://arxiv.org/abs/1406.6247}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/gru.hpp b/src/mlpack/methods/ann/layer/gru.hpp
index 6a863d4488..ef82ce0e82 100644
--- a/src/mlpack/methods/ann/layer/gru.hpp
+++ b/src/mlpack/methods/ann/layer/gru.hpp
@@ -13,7 +13,8 @@
                   Kyunghyun and Bengio, Yoshua},
  *    booktitle = {ICML},
  *    pages     = {2067--2075},
- *    year      = {2015}
+ *    year      = {2015},
+ *    url       = {https://arxiv.org/abs/1502.02367}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/recurrent_attention.hpp b/src/mlpack/methods/ann/layer/recurrent_attention.hpp
index 66993b31ab..4152b4058f 100644
--- a/src/mlpack/methods/ann/layer/recurrent_attention.hpp
+++ b/src/mlpack/methods/ann/layer/recurrent_attention.hpp
@@ -35,11 +35,12 @@ namespace ann /** Artificial Neural Network. */ {
  *
  * @code
  * @article{MnihHGK14,
- *   title={Recurrent Models of Visual Attention},
- *   author={Volodymyr Mnih, Nicolas Heess, Alex Graves, Koray Kavukcuoglu},
- *   journal={CoRR},
- *   volume={abs/1406.6247},
- *   year={2014}
+ *   title   = {Recurrent Models of Visual Attention},
+ *   author  = {Volodymyr Mnih, Nicolas Heess, Alex Graves, Koray Kavukcuoglu},
+ *   journal = {CoRR},
+ *   volume  = {abs/1406.6247},
+ *   year    = {2014},
+ *   url     = {https://arxiv.org/abs/1406.6247}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/reparametrization.hpp b/src/mlpack/methods/ann/layer/reparametrization.hpp
index 6de3f0862d..52049b7bf1 100644
--- a/src/mlpack/methods/ann/layer/reparametrization.hpp
+++ b/src/mlpack/methods/ann/layer/reparametrization.hpp
@@ -39,7 +39,8 @@ namespace ann /** Artificial Neural Network. */ {
  *              Xavier Glorot, Matthew Botvinick, Shakir Mohamed and
  *              Alexander Lerchner | Google DeepMind},
  *   journal = {2017 International Conference on Learning Representations(ICLR)},
- *   year    = {2017}
+ *   year    = {2017},
+ *   url     = {https://deepmind.com/research/publications/beta-VAE-Learning-Basic-Visual-Concepts-with-a-Constrained-Variational-Framework}
  * }
  * @endcode
  *
diff --git a/src/mlpack/methods/ann/layer/weight_norm.hpp b/src/mlpack/methods/ann/layer/weight_norm.hpp
index ed4814943f..b07ee30e48 100644
--- a/src/mlpack/methods/ann/layer/weight_norm.hpp
+++ b/src/mlpack/methods/ann/layer/weight_norm.hpp
@@ -42,7 +42,8 @@ namespace ann /** Artificial Neural Network. */ {
  *            Training of Deep Neural Networks},
  *   author = {Tim Salimans, Diederik P. Kingma},
  *   booktitle = {Neural Information Processing Systems 2016},
- *   year = {2016}
+ *   year = {2016},
+ *   url  = {https://arxiv.org/abs/1602.07868},
  * }
  * @endcode
  *