Most of the UToledo Libraries shelve books according to Library of Congress (LC) Call Numbers. Each letter designates a broad subject area and is further divided into two letter subjects and then by a number
The letter T represents Technology in general
TA Engineering (General). Civil engineering
TC Hydraulic engineering. Ocean engineering
TD Environmental technology. Sanitary engineering
TE Highway engineering. Roads and pavements
TF Railroad engineering and operation
TG Bridge engineering
TH Building construction
TJ Mechanical engineering and machinery
TK Electrical engineering. Electronics. Nuclear engineering
TL Motor vehicles. Aeronautics. Astronautics
TN Mining engineering. Metallurgy
TP Chemical technology
Macmillan Encyclopedia of Energy by 
Sustainability at the Cutting Edge by 
Green Building and Sustainable Development by 
Environmentally Conscious Alternative Energy Production by 
Sustainable Water for the Future by 
Handbook of Energy Efficiency and Renewable Energy by 
Energy Sustainability Through Green Energy by 
Megatrends for Energy Efficiency and Renewable Energy by 
Energy, Sustainability and the Environment by 
Sustainability and Environmental Impact of Renewable Energy Sources by