Ианева, Марияна, Николай Цонев, Мая Василева, и Стелияна Басмаджиева. „Enhancement of Competitiveness of the Product in the Tourist Business by Health Tourism Marketing Management“. Научни трудове, no. 2 (Май 22, 2018): 89–108. отворен на Юли 22, 2026. https://bjiep.e-dnrs.org/index.php/rp/article/view/5569.