First, of the three astronomy books mentioned, only this one mentioned comets as a source and another, as mentioned above, discountsd small particles almost entirely.
This leads me to believe that the comet source theory might not be an agreed upon answer.
Comets are supposedly diverted from the reservoir by the influence of passing stars.
The question is whether or not enough comets will be supplied by this mechanism to agree with observations.
In Exploring the Universe (Holt, Rinehart and Winston, 1969) -- my college astronomy text -- George Abell says: "The fact that we find small particles around the earth is evidence that they are either newly formed or have newly arrived in our part of the solar system." (page 365).
However, since the "young" and "old" age ranges differ by 5 1/2 orders of magnitude, it is easy to say which pieces of evidence favor which theory.Paul Joss, of the Institute for Advanced Study in Princeton, NJ, gives a value of 70 as an average.("On the Origin of Short-Period Comets," Astronomy and Astrophysics, 1-273, June, 1973).Paul Joss, in the above cited reference, calculates "no," by a factor of 40,000. H Delsemme ("Origin of Short-Period Comets," Astronomy and Astrophysics, 7-381, December, 1973) calculates that the answer is "yes." Edger Everhart (University of Denver), who has reviewed both calulations and has contributed his own theories ("Evaluation of Long- and Short-periord Orbits," Comets, edited by Laurel L.Wilkening, University of Arizona Press, 1982), the answer is unknown.If such a source of comets exists, observations are consistent with an old solar system.