https://en.wikipedia.org/wiki/QR_code
What size should it be?
Minimum QR Code Size = Scanning Distance / 10
Minimum QR Code Size = (Scanning Distance / Distance Factor) * Data Density Factor
https://blog.qrstuff.com/2011/01/18/what-size-should-a-qr-code-be
Dynamic QR codes allow to change the pointer from the QR code at any time. Most the time for a fee.
Static QR codes are always pointing to the same location.
Pictorial AR Tag with Hidden Multi-Level Bar-Code and Its Potential Applications
http://www.mdpi.com/2414-4088/1/3/20/htm
Multiple options. Plus. Free Logos
https://www.qrcode-monkey.com/
Some logo ideas
http://blog.visualead.com/qr-code/
Various formats available here. Adds a logo for a fee.
https://www.qrstuff.com/
This website comes with a free QR software, and it also allows for creating QR codes for events, contacts, wifi, business cards, phone, text messages, …
http://barcode.tec-it.com/en
http://zxing.appspot.com/generator/
https://www.barcodesinc.com/generator/index.php
https://www.tec-it.com/en/download/free-software/qrcode-studio/Download.aspx
Paid service for logos:
http://en.qrcode-pro.com
GitHub software for procedural R code generation:
https://github.com/jeromeetienne/jquery-qrcode
