1. https://optiper.com/products/point-source-microscope
2. https://opt-e.com/wp-content/uploads/2016/02/Opt-E-W2-2016-02-13-1.pdf
3. http://trioptics-usa.com/products/opticentric
4. https://www.optoalignment.com/las-bt-vis
5. Practical alignment using an autostigmatic microscope