Levens, A. S., Edstrom, A. E., & French, T. E. (1966). Problems in mechanical drawing: With emphasis on freehand sketching ([3d ed].). Webster Division, McGraw-hill.
Citação norma ChicagoLevens, Alexander Sander, Alfred E. Edstrom, and Thomas Ewing French. Problems in Mechanical Drawing: With Emphasis on Freehand Sketching. [3d ed]. St. Louis, Mo: Webster Division, McGraw-hill, 1966.
Citação norma MLALevens, Alexander Sander, et al. Problems in Mechanical Drawing: With Emphasis on Freehand Sketching. [3d ed]. Webster Division, McGraw-hill, 1966.
Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.