website, it is, as far as I can ascertain, unpublished.
[EDIT, 12 Jan 2015: The link above seemed not to work, so I have changed it. You can also try going to the search page, then under the "Browse Subjects by letter" heading, select "P" and then "Palaeography"]
Unfortunately, almost nothing survives of the upper script-sample, but arguably what remains is the most indicative part: the bottoms of the minims:
The next sample has its medieval name, "fracta", written on a scroll directly above it:
The text itself appears at first glance to be gibberish, as if meant only to give a general visual impression of the script:
|"mimi numinum nivium|
minimi munium nimium
vini muniminum imminui
vivi minimum volunt"
A comparable fragmentary sheet, now in The Hague, gives an idea of the wider range of scripts that might have been represented on the Philadelphia sheet before it was trimmed:
 Katherine Chandler of the Free Library kindly informs me that they have no record of the fragment having been published. The main studies of such objects are:
- S.H. Steinberg, 'Medieval Writing Masters', The Library, 4th Series, 22 (1942), pp. 1-24.
- S.H. Steinberg, 'A Hand-List of Specimens of Medieval Writing-Masters', The Library, 4th Series, 23 (1942), pp.191–94.
- Carl Wehmer, 'Die Schreibmeisterblatter des spaten Mittelalters', Miscellanea Giovanni Mercati, VI, Studi e Testi 126 (1946), pp.152–53.
- S.J.P. van Dijk, 'An Advertisement Sheet of an Early Fourteenth-Century Writing Master at Oxford', Scriptorium, 10 (1956), pp.47–64.
- Martin Steinmann, 'Ein mittelalterliches Schriftmusterblatt', Archiv für Diplomatic, 21 (1975), pp.450–58.