Singh,Soubam Prenchandra. (2018). Eco.tourism environmental problems & sustainable development. Discovery publishing House.
Chicago-viite (17. p.)Singh,Soubam Prenchandra. Eco.tourism Environmental Problems & Sustainable Development. New Delhi: Discovery publishing House, 2018.
MLA-viite (9. p.)Singh,Soubam Prenchandra. Eco.tourism Environmental Problems & Sustainable Development. Discovery publishing House, 2018.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.