Found the following hamletworks.org entries referring to line 543

View Commentary Note for 543
543 This aboue all, to thine owne selfe be true1.3.78

View Immaterial Textual Note for 543
543 This aboue all, to thine owne selfe be true1.3.78

View Material Textual Note for 543
543 This aboue all, to thine owne selfe be true1.3.78