1. A method for distributing electronic content related to paper documents, the method comprising: receiving at a server, an image of at least a portion of a page of a paper document, the image captured by a device of a user reading the paper document, the device communicatively coupled to the server; determining a page layout of the page of the paper document based on the image, the page layout including a spatial arrangement of elements of the paper document with respect to the page; correlating the page layout of the page of the paper document with page layouts of a plurality of electronic documents by an image based comparison, each electronic document comprising markup language page elements that collectively reconstruct the electronic document while preserving page layouts of a corresponding paper document, the correlating further comprising: using linear discriminant analysis to determine low-dimensional structures of the received image and of the plurality of electronic documents; and establishing a correlation factor between the received image and each of the plurality of electronic documents, the correlation factor based upon the low-dimensional structures; identifying, based on the correlation, one of the electronic documents best matching the page of the paper document; retrieving additional electronic content related to the identified document; and sending the additional electronic content to a connected device of the user for display to the user.
1. A method for distributing electronic content related to paper documents, the method comprising: receiving at a server, an image of at least a portion of a page of a paper document, the image captured by a device of a user reading the paper document, the device communicatively coupled to the server; determining a page layout of the page of the paper document based on the image, the page layout including a spatial arrangement of elements of the paper document with respect to the page; correlating the page layout of the page of the paper document with page layouts of a plurality of electronic documents by an image based comparison, each electronic document comprising markup language page elements that collectively reconstruct the electronic document while preserving page layouts of a corresponding paper document, the correlating further comprising: using linear discriminant analysis to determine low-dimensional structures of the received image and of the plurality of electronic documents; and establishing a correlation factor between the received image and each of the plurality of electronic documents, the correlation factor based upon the low-dimensional structures; identifying, based on the correlation, one of the electronic documents best matching the page of the paper document; retrieving additional electronic content related to the identified document; and sending the additional electronic content to a connected device of the user for display to the user. 6. The method of claim 1 , wherein the additional electronic content is a test related to the identified document.