I worked on a small prototype for a client. As part of the delivery I need to transfer copyright and full rights to reuse and redistribute the code that I have written.
I found some text to transfer ownership of images and videos on Google, but I need something specific to code written.
The work was produced in New Hampshire, United States.
Does your client have a legal department or a legal firm that they do busines with?
I would expect the client to write up the documents and have you sign them.
If nothing else turns up, you could try taking one of the Open Source licenses and re-phrasing it so it applies to your client only. Maybe one of the licenses at Creative Commons suits for your purpose, they "link" to a range of OSS licenses.