1. Pilkington, https://www.pilkington.com/en-gb/uk/products/product-categories/self-cleaning/pilkington-activ-range, accessed April 2020.
2. The Concrete Society, http://www.concrete.org.uk/fingertips-nuggets.asp?cmd=display&id=826, accessed April 2020.
3. Deutsche Steinzeug, https://www.deutsche-steinzeug.de/en/news/presse_und_news_detail.html?nd_ref=2530, Accessed April 2020.
4. Sto South East Asia, https://www.sto-sea.com/en/about-sto/sto-innovations/stocolor-climasan-/sto-climasan-color-.html, accessed April 2020.
5. Novel low-temperature photocatalytic titania films produced by plasma-assisted reactive dc magnetron sputtering