Opening (for business letter or article)

1. On behalf of... I am writing to..
2. I am writing in response to the letter dated..regarding...
3. I refer to the letter which appeared in the South China Morning Post on.. entitled "" regarding...
4. The article aims at...
5. The aim of the article is to...
6. it is our greatest pleasure to invite/welcome you to....
7. I am writing to express my concern about...
8. I am writing to complain about
9. Many controversies surround...