I received an email from a travel agency which said:
"A personalized travel itinerary has been sent to you
courtesy of Your Worldspan Travel Agency and My Trip and More."
Then I checked
http://www.askoxford.com/concise_oed/courtesy?view=uk to find that 'by' can be omitted, which got me wondering why it can.
I thought it should be either:
"A personalized travel itinerary has been sent to you
by courtesy of Your Worldspan Travel Agency and My Trip and More," or
A personalized travel itinerary has been sent to you
, a courtesy of Your Worldspan Travel Agency and My Trip and More."
If the omission of by is acceptable, could someone give me some other examples?