Active band pass filter that looks like a sallen–Key topology filter
The shown circuit is one of the classical bandpass topologies - multi-feedback (MFB), however, with a modification proposed by Deliyannis. This modification consists of some additional positive feedback. The circuit can never "latch" because for DC we have 100% negative feedback.

Advantage: Without positive feedback relatively high Q-values (high selectivity of the bandpass) require a high component spread and/or a very large midband gain. This can be avoided using the shown positive fedback path. This modification was proposed by T. Deliyannis in 1968 (Ref. Electronic Letters, vol. 4, page 577). 

Remember the Sallen-Key principle, where a Q-enhancement is achieved solely by using posive feedback (using a fixed positive gain amplifier).

Comment:
It can be shown that this Deliyannis-modification leads to the best trade-off (for high Q values) between moderate midband gain and low component spread. A very large component spread is to be avoided because it either leads to an unwanted low input impedance or very large resistor values in the vicinity of the idealized opamp input resistance. Furthermore, excessive midband gain would challenge the slew rate of the amplifier as well as the input drive capability of the succeeding stage.