A supplemental information system is described herein that uses physical references placed throughout a property to provide extended information about the property to a potential buyer or other interested party. A seller or seller' s agent describes various items of the property in electronic form. The seller associates each item description with a physical reference, such as a QR code. Next, the seller prints out and affixes the physical reference to the item of interest. Potential buyers or others interested in the property can use a smartphone or similar device with a physical reference reading application to read the physical reference and retrieve the supplemental information. The reference may also change behavior over time or provide different information based on the requesting user. Thus, the system makes it easy for real estate sellers and others to connect extended electronic information with physical real estate items.