<http://schema.org/item>
<http://solarwiki.ucdavis.edu/The_Science_of_Solar/Solar_Basics/D._P-N_Junction_Diodes>
<http://solarwiki.ucdavis.edu/The_Science_of_Solar/Solar_Basics/D._P-N_Junction_Diodes/I._P-Type%2C_N-Type_Semiconductors>