Robertson, S., & Bertling, T. How to draw: Drawing and sketching objects and environments from your imagination.
Čikaški stil citiranja (17. izdanje)Robertson, Scott, i Thomas Bertling. How to Draw: Drawing and Sketching Objects and Environments from Your Imagination.
MLA način citiranja (8. izdanje)Robertson, Scott, i Thomas Bertling. How to Draw: Drawing and Sketching Objects and Environments from Your Imagination.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.