Ph\u01b0\u01a1ng ph\u00e1p v\u00e0 c\u00e1c d\u1ea1ng to\u00e1n v\u1ec1 quan h\u1ec7 vu\u00f4ng g\u00f3c trong kh\u00f4ng gian – r\u1ea5t hay<\/a><\/blockquote><\/iframe>