While looking through some of the microfilmed city directories at Carnegie Library, I happened to see that from 1901 through 1909, the years that I researched, there is a separate section after the Pittsburgh-Allegheny entries for Edgewood, Etna, Millvale, Sharpsburg, Swissvale, and Wilkinsburg. While using the 1885 directory, I found a separate section for Knoxville Borough after the Pittsburgh entries. I don't know if any other years have supplements, but if you have relatives who lived in these districts, it may be worth looking. Judi