you have to cite

reason as follows,

first, the concern that you have seen the recommendation letter is not valid, since when you , all the letters attached is open

second, the immigration officers usually spend 30 mins on your case, thus, it is essential to let him get the whole pic right way, directly from the petition letter. So, you HAVE TO include all the important sentences, informations, in those recommandation letter, the officer will NOT have time to go to individual letters to read everything. The letters are there for them to check, in case they really want to.

My LD is working as a legal assitant to immigration lawyers, it is a common practice to cite the key information in the petition letters.