Researchers currently assume that these notes refer to lists, reports or files which were the source of information about where a DP had moved. The abbreviation between the two slashes – “IT 77” in this case – refers to the number of the DP camp. According to a list preserved in the Arolsen Archives, “IT 31” stands for the camp in Bari, “IT 33” for the one in Rome and “IT 48” for the one in Bologna. An overview can be found here.