"Once Hazrat Abdullah bin Umar (RA) was playing with Hazrat Imam Hassan and Hazrat Imam Hussain (RA). At that time Hazrat Imam Hassan (RA) passed a remark on Hazrat Abdullah bin Umar (RA) calling him the son of his slave. Hazrat Abdullah bin Umar (RA), went back home crying and when asked by Hazrat Umar (RA), narrated the whole story. Hazrat Umar (RA) started crying and asked his son to go back to Hazrat Imam Hassan (RA) and request him to write these same words for Hazrat Umar (RA) as a token of authentication to be placed in his coffin."
Is this statement true?? any reference for it??