@article{d3e519cf84c64f4ab6ab2732fbbfd247,
title = "Gravitational Analysis in Regional Science and Spatial Economics: A Vector Gradient Approach to Trade",
keywords = "gravity theory, spatial interaction models, social physics, entropy, gravity potential, distance friction, elasticity, vector gradient, DISTANCE, LAW, ACCESSIBILITY, MONOPOLISTIC COMPETITION, BORDERS, BUSINESS, GRAVITY EQUATION, MODELS, GROWTH, SOCIAL NETWORKS",
author = "Peter Nijkamp and Waldemar Ratajczak",
year = "2021",
month = may,
doi = "10.1177/0160017620980519",
language = "English",
volume = "44",
pages = "400--431",
journal = "International Regional Science Review",
issn = "0160-0176",
publisher = "SAGE Publications Inc.",
number = "3-4",
}