Quomodo Turris ad cuius Basim progredi nequeas; altitudinem dimetiaris?; Altitude measurement of a tower from afar with a sun quadrant and mirror; Fig. 15; p. 43; 1533; Petrus Apian: Horoscopion Apiani generale dignoscendis horis cuiusqumque generis aptissimum [...]. His accedit distantia[rum]; altitudinum; & profunditatum per idem hoc instrumentum dimetiendarum ratio longe accuratissima & ingeniosa [...]. [Ingolstadt]: [Apianus]; [1533]