The Book of Mosques and Places of Prayer
وَحَدَّثَنَاهُ ابْنُ أَبِي عُمَرَ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ الصَّمَدِ، عَنْ مَنْصُورٍ، بِإِسْنَادِ هَؤُلاَءِ وَقَالَ " فَلْيَتَحَرَّ الصَّوَابَ " .This hadith has been narrated by Mansur and he said:" He should aim at correctness
From Sahih Muslim, whose reports the scholars accept as authentic.