Reference (1) is an very good resource. However, physicians who are just beginning their point of care ultrasound study don’t need this article. It is not really that technical but it would not be very clear to someone just starting out. Instead see my post, Getting Started With (Learning) Point Of Care Ultrasound (POCUS).
Also see Dr. Weingart’s podcast and show notes on the Rapid Ultrasound For Shock and Hypotension (RUSH) exam. Dr. Weingart states that the entire exam can be completed with only a curvilear probe.
Of course, it would be optimal for all physician ultrasonographers to have a linear, a curvilinear, and a phase array probe but the best can be the enemy of the good.
An interesting system to look at for office practice is the Phllips Lumify (not an affiliate link). The system has three probes available (linear, curvilinear, and phased array).
There are many other ultrasound systems to consider.
The following is from Reference (1):