Reference documents includes applicant support forms ("lettre d'appui"), letters of reference, referee assessment forms, letters of reference from program directors and Family Medicine (FM) program directors’ assessment forms.
To know which -and how many- reference documents a program is requesting, please review the "Supporting Documentation" section of the program's description. Programs descriptions of a given match can be found here: https://www.carms.ca/program-descriptions/
At this time, some programs in Québec for the R-1 match are requesting a standardized "lettre d'appui / formulaire d'appui" (the same form is used across disciplines and universities). This is with the exception of R-1 Dermatology programs in Québec, that have their own Dermatology applicant support form.
Additionally, the R-1 University of Manitoba / Anesthesiology program requests their own applicant support form.
Note: this is not a definite list of programs that require these forms. You must review program descriptions of programs you're applying to, to ensure you're submitting the correct reference documents.