Frequent Documents, The Sign of the written resources of Al-Kafi

One of the validation ways of the Hadith books is to study their resources. Sheik Saduq and Sheik Tusi had mentioned their books'' resources، since Sheik Kulayni had not specified and among Al-Kafi''s documents also there are no words which refer to the written quotation of these documents. This makes an uncertainty that Al-Kafi''s hadiths، are group of the oral quotations، and they have no reliance on the written resources، so they have affected by the oral quotation''s damages. Therefore، studying of the resources of Al-Kafi has special importance. This article- by the new study which has done about the frequent documents- wants to prove that Sheik Kulayni had utilized the written resources، and after introducing of the different types of the document repetition، its effects and the examples of the frequent documents، proceeds to show this implication. Through this means، the connection between Al-kafi and the writings of the companions of Imams (p. b. o. t)، has been proved and some of the resources of this book has been specified.