This is the best design. But requires the most time and skill to build.
this design uses all metal and shows how to modify a foot valve
this design has math formulas for ram pumps.
Also has a waste valve design similar to the rife pump.
These 3 PDF’s go together.
this design is all plastic, and the least expensive.
this PDF has flow rare and lift charts.
this site has a lot of cool books for free on lots of DIY subjects.
this link has USDA technical notes and links to commercial manufactures.
this PDF has indo and math for basic site development