Some files for using the lm13700 operational transconductance amplifier (http://www.ti.com/lit/ds/symlink/lm13700.pdf) with LTspice
This model is from here: http://www.idea2ic.com/LM13600/SpiceSubcircuit/LM13700_SpiceModel.html
I have added a VSS terminal for working with split supplies, and have consolidated the default transistor models and the LM13700 subcircuit into one .sub file
I have also created a symbol for LTspice for use in the GUI.