The following two articles published in the Journal- **AIP Advances** (March 2011) suggest a classical mathematical model for a basic particle electron, by studying the requirements of Quantum Mechanics and Special Relativity. The model is then expected to give same results in a mathematical analysis as obtained by experiments and suggested by these theories. They are available in the Review Section:

**1.** Mathematical Model I. Electron and quantum mechanics

https://physicsoverflow.org/45309/mathematical-model-i-electron-and-quantum-mechanics

**2.** Mathematical model II. Basic particle and special relativity

https://physicsoverflow.org/45308/mathematical-model-basic-particle-and-special-relativity

The main **LIMITATIONS** of the approach are:

**a).** We need a complete and well defined system to generate any classical model of a physical reality.

**b).** The model of a basic particle can be relative to another particle, with which it interacts. Say, electron as seen by proton, in a Hydrogen atom. The human observer’s role is limited to observing the effects of interaction within these two particles, such as emission of a photon, using his measuring instruments. The concept of describing a classical model of the basic particle as seen by the human observer needs to be discarded.