National Learning Corporation. (2005). Sanitation worker: Test preparation study guide questions & answers. National Learning Corporation.
Цитирование в стиле Чикаго (17-е изд.)National Learning Corporation. Sanitation Worker: Test Preparation Study Guide Questions & Answers. Syosset, N.Y.: National Learning Corporation, 2005.
Цитирование MLA (8-е изд.)National Learning Corporation. Sanitation Worker: Test Preparation Study Guide Questions & Answers. National Learning Corporation, 2005.
Предупреждение: эти цитированмия не могут быть всегда правильны на 100%.