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I suppose he means literature or reading material. BTW, material doesn't have an 's'. The kind of word like equipment. Many material. One material.
There are plenty examples on the Internet and textbooks.
Filters can be designed using passive or active devices. You need to specify accordingly such as Passband, Stopband, Transition band, Gain, -3db Cutoff Frequency, Poles and Order. Sometimes Insertion Loss is also considered. Zeros are not usually not considered in filter design because these have no impact.