Secret Door Bookcase : 18 Steps (with Pictures) - Instructables
The Murphy Door 4 in. x 1.5 in. x 0.25 in. Steel Black Powder Coated Flush Mount Hidden Bookcase Door Hardware with Removable Pin FMHD - The Home Depot
Invisidoor Hinge & Book Pull – The Library Ladder Company
How to Build a Hidden Door Bookshelf: 6 Steps (with Pictures)