Sahih Muslim , Book 15, Hadith 469 (In-Book)

This hadith has been narrated on the authority of Qatada with the same chain of transmitters and he said: " More than three (days) except in the company of a Mahram."

وَحَدَّثَنَاهُ ابْنُ الْمُثَنَّى، حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ سَعِيدٍ، عَنْ قَتَادَةَ، بِهَذَا الإِسْنَادِ وَقَالَ ‏ "‏ أَكْثَرَ مِنْ ثَلاَثٍ إِلاَّ مَعَ ذِي مَحْرَمٍ ‏" ‏ ‏.‏

sunnah.com