1. An information processing apparatus comprising: a memory; a processor in communication with the memory, wherein the information processing apparatus is configured to perform a method, the method comprising: detecting, from a plurality of texts, quotations from other texts, by a detection unit having a matching unit for determining that a character string included in a text is a quotation from a reference target when the character string is included in information obtained by accessing the reference target designated by reference target information included in the text; deleting or replacing with predetermined character strings the quotations in a plurality of the texts in the memory; and executing text mining for a plurality of the converted texts, the text mining unit calculating the degree of similarity between information available from reference targets associated with different quotations of different contents, grouping the quotations based on the degree of similarity, and grouping two or more of the quotations when information available from reference targets associated with two or more of quotations of different contents includes reference target information designating an identical reference target.