Source documents

I would like to know if i am correct i the following:

are the following documents source document? The answers are mine and i would like someone to correct me if i am wrong

list of suppliers…..no
invoice….yes
delivery note…yes
GRN .. yes
Pay-In slip…yes
Quotation .. yes
Letter of Acceptance .. yes
Counter Foil of a cheque…yes

please let me know if these answers are correct. add any documents that may cause confusion ….

Thanks in advance!