ocr: DHOHPTIO a KHI OFUHOLOCEIS worh H Availlab le mtormation about UFOS are too much. - - STOF : Their quality: isgenerally low orevenvery low, * Anyway, it is hecessary to dealwith them, aso for studies where mtormation reliability is notbasic. Paper-hased docunents are becoming ore and more lifficult (and costly) to manage.
