Copyright – ER Software

A copyright notice consists of three elements that generally appear as a single continuous statement [1]:

The copyright symbol © ; the word “copyright”; or the abbreviation “copr.”;
The year of first publication of the work; and
The name of the copyright owner.

If you keep a mix of old and new content in your copyrighted medium, your copyright date may be a range rather than a single year [2]. This shows the copyright protection covers all updates or revisions made during the period listed on the work [12].

When writing software for your employer all copyrights explicitly belong to your employer, unless you explicitly agree to other terms in your contact [3].

An optional fourth component is a statement of rights [2]. A statement of rights is not a requirement. By default, a copyright notice will work to reserve all of your rights, so stating something like “All Rights Reserved” isn’t technically necessary.
However, it is commonly seen this way and clarity of your rights can’t hurt.

Every component of a published software package should contain a copyright notice. This includes [4]:

The package or box the software comes in, if any;
The manual and other written documentation;
The computer disks or other media containing the software (if any); and
The appropriate computer screens.

A software license is a “contract” that allows others from using your code. Restrictions may apply on how “it can be used” and explicit terms may be imposed prior to using it [3]. There are both proprietary licenses [5] and open source licenses [6].
Some of more popular open source licenses [7], from by the number of conditions [8,9,10]:

GNU GPLv3
GNU LGPLv3
Apache License 2.0
MIT License

MIT is one of the most permissive free software licenses. Basically, you can do whatever you want with software licensed under the MIT license – only if you add a copy of the original MIT license and copyright notice to it [10].

To apply the Apache License to your work, attach the following boilerplate notice [11]:

Copyright [yyyy] [name of copyright owner]
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.