Add license and link to resnet.
+# https://github.com/tensorflow/models/blob/master/research/resnet/resnet_model.py
+#
+# Copyright 2016 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+"""ResNet model.
+
+Related papers:
+https://arxiv.org/pdf/1603.05027v2.pdf
+https://arxiv.org/pdf/1512.03385v1.pdf
+https://arxiv.org/pdf/1605.07146v1.pdf
+"""
from collections import namedtuple
import tensorflow as tf
