Where can you buy guest posts like these ?

Hi

Where can you buy guest posts like these –

http://www.vodafone.com/business/blog/gigabit-thinking/how-a-smart-grid-can-empower-a-smart-city
http://www.directenergy.com/blog/how-to-replace-shower-head/
https://www.networkworld.com/article/3236033/energy/how-a-smart-grid-can-empower-a-smart-city.html

They look somewhat good quality.