·The Start：
Dear Sir or Madam
·To Whom It May -（very formal as you do not know the person to whom you are writing）
·Giving Reference：
With referenbsp;to your advertiment（ad）in...
Regarding your advertiment（ad）in...
·Requesting a Catalog，Brochure，etc.：（After the reference，add a a and tinue），would（could）you plea nd me...
·Requesting Further Information：I would also like to know...
Could you tell me whether...
·Signature：
Yours faithfully -（very formal as you do not know the person to whom you are writing）
·The Start：
Dear Sir or Madam
·To Whom It May -（very formal as you do not know the person to whom you are writing）
·Giving Reference：
With referenbsp;to your advertiment（ad）in...
Regarding your advertiment（ad）in...
·Requesting a Catalog，Brochure，etc.：（After the reference，add a a and tinue），would（could）you plea nd me...
·Requesting Further Information：I would also like to know...
Could you tell me whether...
·Signature：
Yours faithfully -（very formal as you do not know the person to whom you are writing）