The fluid mosaic model of membrane structure was proposed by:
Fluid mosaic model, proposed by Singer and Nicolson, is a more recent and acceptable model for membrane structure. 
The biological membrane usually have a thickness of 5-8 nm.
A membrane is essentially composed of a lipid bilayer.
The hydrophobic( nonpolar) regions of the lipids face each other at the core of the bilayer while the hydrophilic( polar) regions face outward.
Globular proteins are irregularly embedded in the lipid bilayer

Key Concept:
Fluid mosaic model was proposed by Singer and Nicolson
Ref : Textbook of Biochemistry, Satyanarayana
Singer and Nicolson
Danielle
Overton
Gorion