Complex sentence: It is often cited by historians, as are the 170,000 typed pages of candid diaries that Stimson dictated at the end of every day, and which are now in the Yale University Library; parts have been published in microfilm.
Split into simpler sentences: It is often cited by historians, as are the 170,000 typed pages of candid diaries that Stimson dictated at the end of every day. The Diary is now in the Yale University Library; parts have been published in microfilm.