López Camelo, Andrés F. Manual for the Preparation and Sale of Fruits and Vegetables. Food and Agriculture Organization of the United Nations, 2004, p. 6. ISBN 92-5-104991-2. «However, in the case of potatoes (Figure 10), sweet potatoes, and other root vegetables, readiness for harvest is based on the percentage of tubers of a specific size.» Potatoes are technically tubers, not roots, and sweet potatoes are tuberous roots.
